I have this “rule” which might be a bit old, that 1 watt a year costs roughly 1€ (it’s just getting worse).
So over say 5 years (a somewhat reasonable time today I think), your 180watt PC used 8h/d would cost 300€ in power usage.
An older PC with a power hungry GPU could use 400 watts => 666€.
A ThinkPad (ok, it has not a gaming GPU) would be like 50€ and a good used one can be had for 200-300€.
You can also get a 4 to 8 gen Dell tower for 40-140€, add a cheap GPU and you’ll have a Roblox / even Minecraft PC.
If you buy a brand new PC yes that won’t (most probably) be an economical investion concerning power use. But old PCs suck(draw) power and one day it’s probably economically viable to change it for a mor recent one.