We can see it when Bitcoin will be legal because in some countries Bitcoin is banned so you can not pay players with it and then they loose it.
But I don't think that it will happen even when it will be legal because its value is so volatile.
First of all, for the volatility of the bitcoin value I think if the both sides : sender and receiver are agree to be dealing with bitcoin.
Second, the legality of the bitcoin is only a matter of time, sooner or later Bitcoin would be legal and the transactions would increase. Which will engender an explosion of value too. Finally, I want to remind you that with bitcoin everything is possible !
You forgot to consider that the player has to pay tax for the transfer, which means that bitcoin has to be legal in the origin country+destination country in order for the transfer to be legal.
Also the voltality does matter.
The player has to pay a lot of things and he stays with a signicifently smaller amount then he should be receiving, if the bitcoin price decreases, he may stay with nothing or even may stay in a minus.
It is impossible to make player transfers in bitcoin until the price will become stable at some level.