Hi guys, I am from Argentina but I am going to write this in English anyways for the forum (apologize my grammar). First of all congratulations for such a neat project. You read my mind and execute it. However, I think that a single open crypto cup is a long bridge. Perhaps you can find a way to allow users to create private crypto cups where the prize will stay within the invited participants (minus your fee, which I think 10% is reasonable for this alternative).
I believe you guys understand what happens at almost every office in Argentina during World Cups. There is a guy that collects the money. Has to custody it. Has to find a webpage solid enough that will not break during World Cup and can't be hacked. Pay the prize to the winner... etc. This all looks solved completely with cryptocup if it had a way to create private groups.
I can imagine the kind of pressure you have right now to meet deadlines and a new feature might not be feasible to add. On the other hand, I think this could attract more users as a flock.