People wouldn't be so interested in Bitcoin if the existing financial system didn't fail so many people. You don't get the cancer without the defects that cause it.
It shouldn't be possible to deny someone the ability to send or receive money. It sounds like a good idea (down with the bad guys), until you also push for a cashless society, at which point it's equivalent to demanding that they starve to death under a bridge because they have no way to buy food or pay rent. That's how to turn people at the margin into violent criminals.
It should be possible to electronically spend $100 anonymously. It isn't anybody's business what kind of books you want to read, or whether you want to donate to the EFF or your church or Planned Parenthood. Your sex life should be between you and your partner, not you, your partner, Paypal, Mastercard and Bank of America.
The existing system gets things like this wrong, which drives people to alternatives. If you don't like the alternatives, remove the demand for them by satisfying it within the existing system.
Yeah, but maybe something like bitcoin is a cancer on an imperfect system.
If you asked a tumor, maybe it would say, well, the infrastructure of the body I'm living in sucks! There are all these use cases that the immune system and the circulatory system and so on don't handle!