I had a weird idea that the gates are entrances to the dimension where bloody Mary is ( the one that works for loyal) that doesn't explain why he needs gold to open them but whatever
Because gold is magically magic o A o )/
from what I read there's no real magical properties of gold ( sorry that was kinda rude)
Loyal himself is actually a portal/reality jumper he doesn't actually hail from Gaia at all it's just a cover. He uses his hat in the same way the mad hatter did in OUAT to cross dimensions. So he finds all the gates so easily because he can sense portals/other realms being from a different one himself.