What's the BF PRO TOKEN used for?

This is what it means.

Thanks. 

Is this now pay to win with the M433 and exclusive guns?

I wouldn't call it pay to win yet. More like pre-order bonus.

Does this mean, there will be a 3 tier-battle pass?
Free BP - gratis (get a few items)
Standard BP -10,-€ (get most of the items)
Premium BP? - ??,-€  (get all items)

In BF2042 you had only the 2 different ones and/or you could buy enhanced BP for +25lv but with standard paid BP you get everything.
For me it sounds really confusing.

I think it will be something like BlackCell in CoD - premium battle pass with some extra content that can be unlocked only by purchasing it.

If its anything like the 2042 battle pass,  hopefully the devs make everything available, but it depends how fast you want it. Coming from COD / B06, you could do any unlockable in the season / that battle pass for free, but pay to get it faster with caveats. 

Of course they had exclusives skins and stuff outside that season / battle pass that only could be purchased or limited promotion (like had to log in in a date range or play this mode and then that mode disappears after some time) and then sometimes they could tack these on the premium battle pass so its extra items listed in the premium bp only. 

But COD you could get stuff like double / triple XP for yourself and guns by doing the promos like little caesars, or red bull / monster was running and didn't have to pay the 70-100 USD (shoot the premium BP was a lot ). the premium bp was like buying the game again and then some 

I hope EA doesn't do that COD style but dang remember the SW Battlefront loot box thingy . . . that was bad, so a part me is cynical

Well, good thing i did not pre-order yet. 
Sorry to say it, but i do hope you are wrong... 3 different tiers with different prices would show everyone, that EA/Dice is what everyone thinks they are.

I wouldn't imagine that any actual weapons, vehicles, or gadgets will be paywalled. I expect it'll work the same way that the Battlepass does in BF2042, but we'll see how it works before too long.

I hope you are right ElliotLH​