This is a trademark issue-- not copyright. "Likelihood of confusion" on the part of the consumers is the main standard. Seems unlikely a a judge or jury will find that the reasonable consumer will conflate the app and the play.
Well, for one thing the "double up" option is not a part of standard poker. More conspicuously, physical poker involves a high degree of observation/manipulation/etc of human opponents and that is not a part of video poker.
Why do you keep ramming Section 8, DoJ, and Congress down our throats? This sort of regulation, if it were to happen, would be done at the state or local level.