I guess, anybody that creates a new Facebook account now, because he wants to also get the Stellars will fall into the spam category.
tl;dr: Isn't it a legitimate interest, to get something that others get? Or is it just a giveaway for Facebook users? When so, would you please say so in the first place (, that your system is only for them). It does not foster my trust in this new system, when I am locked out, just because I am not inside some "special club" (I don't remember, that Facebook membership is now essential to interact in the internet -- .... I am at the verge to feel discriminated.).
I find it good, to have an alternate payment method to get out of the trap of traditional payment systems, that are dominated by a few big corporations .... and then, what happens, I have to bow to one even bigger monopolist. --> Does not foster my trust into a system that claims to be free and open.