Do I have to worry about useState causing a re-render?

I guess this is expected behavior. If I add a similar console.log to native core blocks that use useState, I get the same effect. It seems that WordPress operates with use strict, and according to this answer, React double-invokes a number of things when in strict mode.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)