Finally started my implementation of a draughts game (which I hope I'll not abandon) after UML-ing it for days, now I'm basically ping-ponging between these two, which helps me rethinking about with more care.
I almost got trapped on the UML rabbit hole, avoided thanks to the tips you gave me!
UML helps planning, but I feel the true advantage comes later actually: it's being easier to remember how your project works by looking at the UML graphs than digging the actual messy thing.