Their purpose is what we decide it is.

Marketing can monitize any interaction. And our interactions are public.

Comment, like, zap, it's all useable marketing data points.

I understand fearing an adverisement takeover, but we also need to communicate. And any communication is a data point.

Likes arent the problem, it's people's willingness to put up with ads.

We all need to encourage everyone to shun and block ads, not attack various forms of communications because marketing agencies will use them for evil.