If you think the point is to pressure change, most of the time, yeah, it's useless.

It's a great opportunity to catch people moving up the radicalization ladder to pull them left.

In more extreme moments with sufficient organization behind them, protests can develop into revolutions such as the fascist counter-revolution in Ukraine in 2014. That obviously didn't change much about the underlying system in Ukraine other than installing a western puppet and further empowering the fascists.