Ironically a lot of people that would have before criticized Wall Street now seem to be spending more effort criticizing cryptocurrencies ? (Even though they are the same kind of people that created and popularized cryptocurrencies to deal with Wall Street's issues in the first place ?)

I have no problem criticizing both.

Indeed, one good criticism of cryptocurrencies is that the are sucking up a lot of the attention and money that could go into actual reform.

For example, contrast Bitcoin usage in emerging markets with something like M-Pesa. They both started at the same time, but M-Pesa has been a huge boon to the unbanked, whereas Bitcoin is a rounding error in those markets.

Any good source to learn what M-Pesa is ?

Help me understand what you need beyond what you'd get from the top 10 Google hits. Because I see 4 or 5 sources there that seem good to me.