That what your supposed to get, plarium wants you to spend money on crates and then get trash instead of something actually good.

Why all the useless damn skins?

I dont get why someone would want skins. They are useless. Thats why all my mecha are default

Skins give the player a sense of being able to express themselves through the mech visuals. No, they don't give any battle bonuses except looking different. However, this game is about more than who is stronger in battle; for some people, it's much like making model airplanes or cars - just with mechs.

But yea, the fortune vault (like all RNG pulls in this game) are rigged to try to convince you to spend more, and more, and more. I've won 1k acorns off a pull once, every other attempt I've made since starting this game has been 1 of the 3 lowest prizes available. 

Why can't rewards be for something you already possess?  It's especially lovely to save up 20 fortune keys to get a skin for a mech you will never get.  It's like a big middle finger to your face.