I always kind of thought of fish in a similar line as flowers, mostly for show, not really for personality. Like plants you don't want them to devour eachother, in the gardening world, some plants are more aggressive in that they'll outgrow their neighbors and take over.
However it would be nice to make a thornless rose in the betta world I think?
I don't mind the spunk, but I do dislike how bettas are loners(there's only so much space in one's house for separation haha).
If mankind genetically engineered a betta with the temperament of a goldfish, would you want it?
I suppose I'd be mostly focusing on, 'at what cost?'