It is true that fb is the biggest social media, but I think it is not relevant in crypto world. In my opinion the biggest advertising on crypto is done on bitcointalk, reddit, twitter, and why not steemit. At least who is really interested on crypto world and who want a technical opinion for cryptos must look at the above mentioned platforms. For me on fb are advertising mostly spam ICO-s that try to collect funds from peoples without any knowledge about cryptos and on that point of view the bann is not affecting the real crypto.