Ofcourse wild card take up a spot!
Its used so you can give your class an upper hand somewhere where normally you shouldn't be able to.
It means you can customise your class a lot better to suit how you want.
It also means you have to choose which one you want to use carefully as it will take 2 slots.
You are gaining extra on top of what the standard class is, and making it 2 tokens means its more balanced.
E.g..
You have 3 attachments whereas I thought il have 3 perks, out class's are completely different however they are balanced!
Wheras if everyone could just pick any extra attachment or perk for just 1 token it would make it less of a risk (as the guy below me said "opportunity cost") and a lot of people's classes would be the same.
tl;dr
If you want extra, you're gonna have to pay for it.
Wildcards cost a slot? *Complaints about it being unfair and taking up too much slots*
Wildcards don't fill up a slot? *Complaints about classes being too OP*
Dumb bullshit you say? I call it opportunity cost.
This ^