Will Warzone be like a mini-loot game?

With req packs and the my exclusive Gamestop BR and MT stuff, along with perk and power weapon cards you can use at certain points of a match, it sounds to me like Warzone is like a miniature loot game within Halo that borrows loot traits from CoD AW, Battlefield, and Titanfall.

With that said, my big question is: Are Warzone gun variants cosmetic only, or do they have their own stats that effect performance. Also, will the inventory space be unlimited?

The gun variants do affect stats, and some have additional attachments, iirc.

They said that you get special ‘bonuses’ on certain cards, but it’s not a constant thing. It’s only one time use.
The stats are barely changed.
Inventory space for cards you mean? I haven’t seen how many cards of EACH you can have, but I would assume you can have at least 5-10 of each.
The miniature loot game doesn’t sound like it’s adequate enough to describe what’s going on.
They allow you to use cards you acquire from playing in ALL game types, not just Warzone, but you can only use the weapon/vehicle cards in warzone. You can use the armor and skin ones everywhere.