I'd honestly say that it's more of a 4C "archetype" at this point, with most of the explicit support living in Rakdos/Jund and Blue loving artifacts in general.
...
As someone who has tried multiple iterations of making a Treasure-themed cube... you really need to nail down exactly what you want Treasures to do in your cube. Because, given the broader card-pool, making a Treasure archetype is kinda like making a "card draw" archetype — you totally can do that, but you can't accomplish it by just jamming together a bunch of cards that say "draw a card" on them.
(TO DO: ACTUALLY INCLUDE EXAMPLES)
...
As someone who has tried multiple iterations of making a Treasure-themed cube... you really need to nail down exactly what you want Treasures to do in your cube. Because, given the broader card-pool, making a Treasure archetype is kinda like making a "card draw" archetype — you totally can do that, but you can't accomplish it by just jamming together a bunch of cards that say "draw a card" on them.
(TO DO: ACTUALLY INCLUDE EXAMPLES)