Work-for-pay tends to be more beneficial to others than 'creative expression'-type activities such as writing, painting, or composing music. The vast majority of what people create is worthless to others, whereas much of what people do 'for work' is actually useful to others.
I’ve occasionally edited Wikipedia, to correct grammatical or factual errors, but I don’t see it as having contributed much to the world.
This not liking vanity thing is interesting but if you tie it to economics then anything that helps people that doesn't make money --things like free software and participating in charities-- could be considered 'vanity' too despite the good they can do.
I got similarly worked up over 'virtue signaling' and people only doing good things for personal prestige when I was an angsty teen but later realised it was better to believe that some people want to do good things sometimes because reasons.