There seems to be a lot of "buzz" lately (the past few years) that modern languages should be immutable-by-default or strive towards it. There seems to be this notation that mutability is bad and I don't know if that's empirically true.
In C/C++, I hardly even use `const` any more because during developing, code likes to mutate and thus a lot of the data does too. It might be that I just very used to the mutable-by-default concept but all the advantages that people advocate about, I don't really have problems with. I understand that being stateless is powerful but being stateful is just as powerful but for different reasons.
Is there any evidence to back up their claims or is it just an opinion that cannot be proven or even just the current "fad"?