I mean, in my 5e tabletop games it's pretty much been stated that everyone really does smell like shit and are covered in various blood and guts until you actually sleep at an inn or visit an establishment with baths, unless stated otherwise. So sleeping in your armor in the wilderness isn't that upsetting to me, immersion wise. In 5e I've never played with any rules about rests needing to be armor free in order to work, but I've never played any heavily armored class either.
I totally understand your point of view here, though. And I welcome any excuse to play dress up with my characters.