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.
When I was a kid in Florida in elementary school, that’s what most elementary schools did, mine was next door to a swimming pool so we just walked. At the time I think it actually was mandated by the state - swimming pools in backyards are extremely common there and it was an upsettingly common occurrence for kids to drown in them, so they took a week to make sure we all knew how to tread water. I don’t know if Florida kids still learn how to tread water or if swimming lessons are now woke somehow.