3 and 7, teleporting a short distance like that can be extremely useful to get past roors and fences. Identifying whether a container was empty or not reliably is good enough proof to clean out this list without being powerful enough that the majority of people would actually believe I have magic, plus I don’t have to reveal my teleporting ability.
It doesn’t make sense for the individual unless you consider that they live in a society. You would be annoyed to have to retrieve a wayward cart and by returning your cart you enforce the expectation and social pressure on others to do the same. I don’t think it’s selfless to treat your environment with respect, it’s in your own best interest most of the time.