UN sparrers have an experience advantage and it's easier to quickly back away a small distance and turn back to slash. I spar on phone and pc. From the first time I tried iphone and android I could win against the best pc players. There is a trade off. I think the phone directional inputs move more smoothly than pushing buttons on a keyboard.
Spar skill has much to do with who complains about fighting pc players. People who get mad when they lose, that complain about "sword spam," "wall sparring," etc., are the ones who still complain about pc sparrers after over 2 years.
What does Rufus know about sparring? The only reason US was winning in the past is because isparrers are so easy compared to UN sparrers. They didn't practice, they don't even like gs, they just showed up on tournament day and won tournaments. Rufus has only won like one tournament on UN when no other good sparrers showed up. He's not considered one of the good ones. You wouldn't know a good sparrer if they flawed you.