Depends on your time horizon.
if you think the reward is just the wage packet for that month then putting in extra hours is crazy. If you think you will get a reward in the long term it’s not.
I reckon I am still way below my potential grade, so am putting in hours to develop skills and gain experience but still have to get the day job done. It’s part of an ongoing education.
I could be wrong about my potential, as most people are, but i’d rather make a c**t of it by trying and failing than by not trying.
If other folk just want an honest wage for turning up at doing a decent job then that’s great.
Too many judgemental folk on both sides here.