There's no point in idempotency for operations that change the state. DELETE is supposed to be idempotent, but it can only be if you limit yourself to deletion by unique, non-repeating id. Should you do something like delete by email or product, you have to use another operation, which then obviously will be POST anyway. And there's no way to "cache" a delete operation.
It's just absurd to mention idempotency when the state gets altered.
> There's no point in idempotency for operations that change the state.
Of course there is
> DELETE is supposed to be idempotent, but it can only be if you limit yourself to deletion by unique, non-repeating id
Which is most operations
> Should you do something like delete by email or product, you have to use another operation,
Erm.... No, you don't?
> which then obviously will be POST anyway. And there's no way to "cache" a delete operation.
Why would you want to cache a delete operation?