For the literal breast plate I would buy

For the literal breast plate I would buy a set for myself (if they came in smaller sizes) as a trans girl. It looks like the construction is supportive (Hopefully) and if it was for cosplay I would imagine they would make it with comfort in mind. I do think it's a ridiculous but maybe it could be rebranded in a more positive light for the trans market

I don’t think it’s necessarily a bad idea.  I just think it’s a little telling of what kind of bodies show up so much in fiction and how skimpy the outfits are.  I think that is also what the OP was going for (the article & comments in it were also a bit creepy, which I think they were also reacting to.)  But I have no problem with the concept or people wearing them.  I can see some potential positives about it (keeps you warm, hides your actual breasts, cosplay for people with small chests, feels like you have a pair of stuffed animals next to your breasts (this is what I like about my bra), etc)

(I tend to make jokes about many things, even things I like.)