I was thinking about that when I was dropping my 6 year old off at some hobbies earlier - it’s pretty much expected to have learned how to ride a bicycle before starting school, and it massively expands the area you can go to by yourself. When she went to school by bicycle she can easily make a detour via a shop to spend some pocket money before coming home, while by foot that’d be rather time consuming.
Quite a lot of friends from outside of Europe either can’t ride a bicycle, or were learning it as adult after moving here, though.
edit: the high number of replies mentioning “swimming” made me realize that I had that filed as a basic skill pretty much everybody has - probably due to swimming lessons being a mandatory part of school education here.
That’s a good anecdote.
For my part I took Spanish from 2nd or 3rd grade all through college. I basically knew enough to be dangerous and it was occasionally useful in online chat where my broken Spanish was marginally better than some people’s non-existent English. But honestly the biggest strength was that I knew enough to be able to tell when Google translate did a bad job conveying my meaning.
Nowadays I’m several years removed from the last opportunity to use it at all and I hardly remember anything. It’s definitely a “use it or lose it” thing.