For what it's worth, I can chip in with my experience on social media advertising this year.
You can target a geographical area - You can, for example, only have your ads show up on Facebook/Instagram or whatever, for people who are actually within your town. Incidentally, this can also be leveraged by a band playing a gig in a new town; just set up an advert and limit it to that one town.
You can target the exact demographic - The data collection on social media is crazy, we all know that. But using it for adverts is then crazy powerful. Alarmingly so. Being able to drill down to limit the delivery of adverts to people who are interested in music technology, and even interested in learning music production, is easy.
You may design a nice looking advert (still graphic or a video even), and get 5k "likes". So you are being told, yes indeed, maybe 15k people saw it, and 5k even clicked "like". What does that translate to? How many hits did your website get because of this? None? Hmmm. Yeah, this is the problem with converting "likes" into something worthwhile, such as people actually signing up for a tuition or buying a course online.
One issue with facebook which has yet to be resolved, is the use of bot networks which are being paid by real people to build up private accounts. These real but then automated accounts go clicking on any and all paid adverts on facebook. I had one running with 1k "likes" per day, only to dive into the details and find they were all from Russian accounts, and were not interested in the product I was offering. So my paid advertising was being eaten up by a bot network, and facebook can and will do nothing about this. I think the only way to prevent this is to geographically limit the exposure.
Another is the extremely annoying AI system which refuses almost every advert I have put on facebook. A request that it be examined by a human then delays the entire process by up to a week. They have a strict policy, such as having to use a capital F when writing facebook (yes, master), only a certain percentage of the advert containing text and other stuff like that. All the adverts I've had which were refused by an AI were then authorized when an operator looked at it, with no changes. So whatever, a minor inconvenience.
The final misfortune with facebook was that they kept asking me to pre-pay on the advert account. After the incident with the Russian bot network, I had pre-paid for a certain exposure, but then decided to pull the advert just after it had started to run. I asked then to close the account and refund the money. They closed the account. Some months later I messaged again about the money. What ensued was a TWO HOUR text chat with one of their operators, who asked for information on exactly how I had paid this pre-paid money and when. It was not sufficient that the funds were on my facebook advert account, but I had to prove to them, when and how the money was transferred to facebook. Luckily I have good internet banking and could go a year back to find the transactions. Between screen-shots of bank records and screen-shots of my mail account to show them what they already knew she said "OK, we have the information now, I'll pass it to the relevant team to decide if they can process your refund". They messaged back a week later to say, due to the Terms and Conditions, they could not process the refund. There was no clause in the T&C to state this, and when I pushed, they stopped writing and tried instead to phone me to avoid any record of what was said.
Will I use facebook advertising again? Yes, absolutely. I have pre-paid money on their system which I will use for something, anything, to avoid that they keep it.
Should you use facebook advertising? That's up to you. It's where the target audience reside. I've been through the handing out flyers, taping posters to telegraph poles and all the like to promote my own music technology training, and it's a lot of work. It's a different experience being able to target the exact audience and watch from the comfort of your mobile device, how many thousand people saw that advert this week. But as mentioned, it's not without it's drawbacks.
As an example, here is a list of keywords I used to promote a psychedelic trance track I released. I was getting around 1800 "likes" per day on a picture of the album cover, for 20 euro per day. Did this translate into sales? No. But there are now thousands of people who saw the band name / single, who are actually in that music scene (have searched for or "liked" one or more of the keywords below).
Example of facebook keywords:
Location: Europe, Age: 18-40, Gender: Male
"Interests: Adventure travel, Techno, Vibrasphere, Meditation, Jean-Michel Jarre, Ecotourism, Tangerine Dream, Music festivals, Goa - Trance Progressive & Psychedelic, The Future Sound of London, Parties, GMS (music group), Electronic dance music, Dance music, Mixmag, Sisyphus, Air travel, DJ Magazine, Aes Dana (ambient group), Etnica, Resident Advisor, Ott (record producer), Underworld (band), Berghain / Panorama Bar (OFFICIAL), Daft Punk, Music videos, Hallucinogen (musician), Nightclubs, Ticon official fanpage, Leftfield, Eat Static, Abacus, Space Tribe, Psychedelic trance, Dance, Beaches, Ozric Tentacles, pioneer dj, Ellen Allien, Audio equipment, Electronic music, Day.Din or Pan-Pot, Behaviours: Frequent international travellers"