It is not only Google that is banning crypto ads.
Facebook is banning crypto aswell but we are talking about Ads.
Twitter goes with the same boat http://fortune.com/2018/03/18/report-twitter-cryptocurrency-ads/

But we could still Share, Retweet , Like etc...
Its all about the paid Ads those will be banned, I have seen many paid Scam Ads on my timeline.
So the good ICO's will get enough support on social media.

I dont think that it will lead to a big problem in the future.
And serious do you even Click on those Crypto Ads.
Bitcointalk and other sources thats where i get my interest in ICO's from.