Honestly, if you take it wide enough, "stimming" is why humans have hobbies and why animals have fun.
Knitting can be stimming.
Running/jogging can be stimming.
Taking looooong showers can be a method of emotional regulation. <- anything can be used for emotional regulation, and a lot of it is actually not just socially accepted but even "advertised".
For example: how often have you come across someone being suggested to "take a hot long bubble bath after a long tiring day"?
Or how often have you seen/read about people "having a glass of wine after a hard day"?
Those things are "regulating emotions" in the way that they help make one emotion go away and/or/by releasing a different emotion.
That's why your* grandmother used to humm while doing laundry, btw.
*not yours personally, more like 'the grandma in all those cutesy stories about someones childhood'