Do I have to use G-Loot servers?

G-Loot does not host the matches in the games, or have any G-Loot servers for the challenges you sign up to with G-Loot.
When you sign up to a challenge in the client, the next match you play in that game, with the G-Loot client just running in the background, will count towards that challenge. So there might be players on the leaderboards in the G-Loot client that aren’t playing on the same server as you.