Mastering isn't a problem as you master it the fair way. What I find annoying in all the PvP games is that people either cheat using software, or they find bugs and glitches that allow them to win against other players and make their experience as bad as possible. This used to be a thing in all shooters, especially battlefield and call of duty series. For this reason while choosing a gambling PvP game you'd have to be prepared to lose money, even if you're a skilled player.

There's also a thing with practice. Would you allow players to play without wagering, just to get to know the game and get better at it before they make their bets? If you do, you'll end up with people experimenting with various tactics and you give them more time to find glitches and bugs they can later use against other players. If you don't do it, the only way to get better would be to put money into the game, so people ready to put a lot of time and money into the game ultimately win more, which makes it a pay to win game.

That said, I'd still choose B, if the game was well made.