Undertale - Floe Shop

Hi this is my friend! flowey!

Hiya! i'm flowey! and this is my friend, flowey!

Don't forget about my friend!

Hi! I'm asriel!

As much as I like Underswap, there are some things I just don't quite understand. Like, why is Temmie, of all characters, swapped with Flowey? Is it because one's sincerely cute, whilst the other is falsely cute (until you help him through his dark-&-edgy teenage phase, at the end of the True Pacifist Run)? Because that's the only fathomable reason I can think of.