I am always open to changing my mind, yet when I see the same untruths mustered to poison-the-well ('swapping ads with their own' - not true) I wonder why the same dishonest and distorted talking points come up instead of any valid criticisms.
What you call 'cryptocurrency nonsense' is a model that potentially threatens to overturn Google's ad model, and with it the current ad-tech ecosystem.
That obviously means there's a huge number of high-stakes players who are very keen for this particular model not to 'take' in the online world, and so we see the same untruths constantly amplified.
Brave must be doing something right, and even if there's a purist's position which says their model is not the holy grail, I'd prefer innovation and disrupted business models over a continuation of the current ad-tech status quo.