Flavorwise sure.Flavorwise, there is an unlimited number of armor types.
Mechanically, magic armor diversifies rewards.
Mechanically.. if the new treasure isn't noticeably better or have a worthwhile tradeoff >50% of players will not care about the new armor you throw in the treasure and will sell or hand it down to henchmen.
This wasn't a problem in older editions as you 4-6 levels of +X to hand out.
But in 5e, giving out +2 armor can really screw up battles.
A Fighter with +2 armor can get to 23 AC easy and make 75% of attacks against him miss.
This means you only have a +1 and +0 range to work with. But 5e's armor don't get top end options to light or heavy armor.