Is violence counterproductive?

The last 10 or is it 12 days have seen violent protests in most cities in the US of A and in some other cities around the world following the police killing or is it murder of George Floyd and there have been arguments about whether the violence is really useful?

I have seen a post that calls the violence immoral and ineffective. Immoral because the destruction of property of bystanders and ineffective because it will not earn the demonstrators any sympathies.

Should the demonstrators adopt only non violent means to achieve their ends?

I want to suggest here a unpopular opinion. That violence seems sometimes to work & its only downside is that it costs lives & property. Independence was warn in many places because of sustained violence against the colonial authorities. America has mastered the art of spreading violence all round ( cloaked in spreading democracy).

What do you think? I am not asking you to support violence but only to comment looking at history if there are situations where violence has led to progress? How can the same be achieved without resorting to violence?