If they mature early, the meat will be less tough. Cooking procedure will alleviate some problems.
I only know one person that had seramas and I think they died of old age so she didn't eat them.
I'm sure if you search on here you'll find serama breeders that eat extra cockerels and can answer...
Well silkies, which aren't much bigger, are a big hit as a meat bird in some communities.
I always say that if a raccoon can find meat on one, so can I.
Meat quality, not just quantity, is another consideration.