i think metorium had a smooth transition into the zylon shop when kenny started selling it to players who asked for it, kinda like how it is with perm ligers right now. perm heads are popular in the giga market tho so it might not be wise to sell it in zylon shop, but it's only a cosmetic so it'll hurt nothing rly
that being said, yah they're in the same boat but cosmetics have no real affect on things in the longrun, only themselves. ds(E) used to be in huge demand in the market for about 1.5bil gigas. it's never sold for that much anymore i believe so there'd be no real loss in selling it in the zylonshop apart from having people who own it QQ about it. metorium is still sold at nice prices and ds(e) would be too, seeing as it's realistically run its course in the market there's no real reason to not redistribute it apart from keeping up its rarity for its own vanity's sake, imo. cosmetics can be sold or kept very limited and it won't make a difference to the game at all, really. price will just go down and we'll see more ds(e) than before, but still not much as it's statistically terrible. even the perm heads like liger will still let your bot build up huge endgame stats, how often do you see top players using metorium to accomplish things like speedruns, raids and grinding sessions?
i think i over-rambled but yeah it'd be a good idea to have crappy cosmetics in the zylonshop if they aren't blowing up in rarity ingame. ds(e) used to be sold for 1.5bil and it's now a lot lower and less cared for, so like i said, the only reason to keep it out of the zylonshop is for its own reputation as a 'rare set that costs a lot of gigas'