voobster

>One of the biggest drawbacks for blockchain is that transactions can't be revoked after the fact

Yes that is a major double-edged sword but it is ultimately a feature of blockchains (at least the base layer), not a bug. Everyone who has ever been a victim of fraudulent chargebacks can vouch for that. If you want reversibility you are free to create a smart contract which allows that using its own token. Frankly I wouldn't want to use a blockchain where someone can acquire my personal info and then social engineer their way into stealing my money, as commonly happens within the traditional financial system.

Probably logarithmic due to diminishing returns. Having 20 nullish types isn't much worse than having 2. The biggest difference is going from 0 to 1.