Every card can change to anything as long as the community creates and makes it public
On the other hand, seeing effects go from common to uncommon (like Doom Blade) is much more controversial, and while almost unheard of, having effects go from common to rare feels horrible because players end up thinking, "Only a few sets ago, I opened this card as a common, and now it's eating up the rare slot where I'm supposed to get an exciting / powerful / playable card?" This psychological feel-bad sums up the biggest problem with the aftermath cards: they simply aren't exciting because nearly all of them feel like commons that you'll open in your rare slot
Cards in mint condition will fetch a higher price than cards in poor condition
A big part of that is this Pokemon's design, and that's the same mentality for these card sleeves
This includes Persistent Petitioners itself on the turn it comes under your control
Teferi, Time Raveler continues the trend of interacting while providing other value, which is just what Elementals wants