Based on my own fetishes I enjoy, I see it somewhat often (As in people being it), and I enjoy being macro just coz I can tease my BF about destroying a mcdonalds.
Otherwise, I usually joke about throwing the micros, whenever it's me finding a micro or someone to me is a micro. Size difference is nice.
To much vore, unbirthing, hyper, and crushing. I like size difference and the prominent foot fetishism is alright but macro/micro by design tends to just be a vehicle for more extreme fetishes.
Considering how common magic is in my own lore, size changing is fairly common to have, although rarely used unless a certain large character wanted to shrink to normal size to fit in say a house. Mostly because being big is commonly a disadvantage unless you are strong enough.I have characters that change size, and an entire family where this is a genetic superpower. They tend to be villains though.