Point 1: Google shows ads as per your general browsing behavior so it's nothing like youtube specifically started showing bitcoin based ads. Even if you visit some random blog hosting google adsense on it, you will see bitcoin based ads.

Point 2: It isn't bitcoin ad actually. The advertisement is from eToro which was started as binary trading site and now shifted to social trading hence accumulated bitcoin trading on it too. These sites stress too much on MLM-based networking by giving huge referral commissions. So it may be possible that the ad you are seeing is actually created by one of the user of eToro who is seeking for new referrals.
Nothing big to create buzz about.