Well, if it’s an online game played on pre-published maps for study, then it’s clear – you know in advance whether you’ll need diplomacy. But if it’s an online game on a random map that players see for the first time when they start the battle, then maybe it makes sense to take and develop diplomacy? By the way, are there any such online tournaments at all, or are online tournaments always played on pre-published maps for study? Honestly, I don’t consider such an online game to be a real online game. It’s practically the same as offline, because players first study the map thoroughly in offline mode on their own. And only then do they give a demonstration performance online.

1. Diplomacy is banned in 9 out of 10 online games.
2. Fixed maps (pre-published maps) are much more balanced than random maps, but they lose a little to random maps precisely because they are published in advance, but usually this is only a couple of days before the start of the tournament, which does not violate the balance, since everyone can study them without exception, but such a tournament still differs radically from offline, because even after studying the map from all sides, the game takes place the first time (without replays), and most importantly – you are playing against a person, not computers (with monotonous behavior) or neutrals!
3. I won’t argue which online game is better, on fixed maps or on random maps, but your point of view is absolutely unfounded.
P.S. I would like to see your so-called “demonstration performances.”