When she said "I play pro.", she was refering to the set of rules by which she plays... referring to the possible slop shot victory on the 8-ball.
I snapped-off a small bar tourney over the weekend and had to work my butt off because we were playing modified last pocket rules with ball in hand... but it was not ball in hand if you could not see the ball you were shooting at and did not hit it. You also did not have to drive a ball to the rail after contact. You also could not adjust the cueball after setting it on the table when you got ball in hand. I was laughing at the tourney director, telling him that he was making the rules up as we went.
On a barbox, any banger can string 4 or 5 balls together on you. Especially if you have foolishly run your balls off without getting out. When they miss, they will always leave you in a crappy position. When a better player misses, the cueball is usually not against the head rail or even tied-up to another ball. I think barbox pool is certainly a test of concentration and self-control. You gotta wait for the right time to finish the game, but you also have to blast it out when you need to.