A pair tournament is such a hassle. Here are some issues:
1) Getting everyone together at the same time (4 people) is problematic.
2) You get together, and someone suddenly has to leave – game over.
3) You get together, and someone's internet starts glitching – you get nervous, game over.
4) You get together, and there's a disconnect, you don't know whose – you get nervous, game over.
5) You get together, start playing – the turn limit is 10 minutes, it's turn-based – the interval between turns can be over 30 minutes, and then the player whose turn it is gets disconnected – you play, sit, and wait.
6) One person has a bug, another has a problem – nervousness, complaints (possibly), and so on.
Personally, what bothers me the most from this list is waiting for my next turn for more than half an hour, and that's if everything else goes well.