If I sell someone a meal and they eat it, I really don't want that money to leave my account, because I have no recourse on my side.
There is an asymmetry here because anyone can be a customer but not everyone can be a vendor- that requires a certain level of reputation and upfront investment. So it is more risky for a vendor to scam a customer than the other way around.
Cryptocurrency transactions require high trust in the sense that they cannot be refunded, but they also require low trust in the sense that the vendor cannot possibly steal any more money than what you sign them.
With an open season of friendly / chargeback fraud, customer lies, refund tricks, etc which customers keep doing every day and so on which too many of that and Amazon will ban your account and they should.
My guess is that if I had no option to do a chargeback, it would have been harder to get a refund then.
Most don't do because convenience wins for the user and increases the value.
The user knows if something is wrong (like stolen funds, accounts etc) they will get their money back, and trusts the system so spends more.
İf you don't provide this trust system, they won't spend as much as they do.
You will get less volume.