Too late. They most likely missed the crypto train. Banning crypto ads and accounts damaged their reputation and it wasn't already in a good shape before it.
It will still create some hype however. It still has a name which is worth millions of dollars. Just a name...
They find the crypto market too small for them, even the current market is not as much as Facebook's value. In addition, most ICO advertisements are fraudulent ICOs, in order to get investors' money, I think their decision to ban ICO advertising is accurate.