There where actually 2 critiques and their practice would count as fraud in a lot of countries.

#1 Money was re-distributed if donated and not claimed -> its not frozen infinite.

#2 There was no way to opt out -> its now opt in iirc

Besides that there are other critique points.

#1 Brave is controlling the add economy. They do this by blocking adds and offering their opt in add service(and gain 30% of the add revenue)

#2 Brave is using its own crypto currency to have full control over the money flow.

What additionally lowers their credibility is that they put false advertisement on their website.

This makes me wounder whats the incent to use brave.