if we would have more of these, the theoretical conversation about SBD wouldn't be necessary.

I agree, but you have to start somewhere, and these cases show that the potential is there. The entire steemit community is very small (probably only a thousand or so very active users) so you just can't expect too many little niches to thrive. But with a large community there can be many of these niches indeed, and larger marketplaces and economies starting to bloom.