What if it was an a.I battle? Also you can pause in the current battle arena because after a match is loaded, you don't need internet until the victory screen to get you +10 MMR.
If it was live, then yeah the net speeds could be a concern. We haven't got live PvP of 1v1 or 2v2 yet as of now but it sounds like it could be in another game of DQ or something. It would be interesting but then the net restrictions can be there (albeit not too huge). 1v1 and 2v2 live PvP would work fine but anymore than that with internet and that's where it's debatable.
Ping and internet advantage.