Negative. Warm-up rounds DO actually have a very big purpose. They allow people to connect to the server and choose their side without having to do so while a game is already in progress. In GG this is particularly big due to the fact of how fast the rounds go. By the time half the people connect and get into the game, the first group of people will already be in their spawn. Warm-up rounds are needed, not so much as to "warm-up" but to allow everybody to get in the game and settled.