Let’s hope for the best then, because that’s a slippery slope.
Grim story time - TLDR at the end
In War Thunder, the custom lobby system with rewards (not to be mistaken with reward-less custom battles) was added to become the game mode of choice for aircraft SIM players. Mirroring “lone wolf”, it was supposed to cater the minority of players who looked for a (somewhat) more hardcore experience.
EXCEPT, it didn’t take long before organized account farmers figured out that the quickest way to farm was to abuse the lobby system. They started creating blatantly unbalanced rooms with all nations vs one, where the “victim” side would be played by puppet accounts and just keep spawning inert new planes, while farmers on the other side would feast on them and rack up enormous amounts of XP and Lions (the free currency). “Normal” players trying to join would soon be mobbed, teamkilled and harassed in any way in order to force them to leave, so they wouldn’t disturb the farming.
“So what? Just leave farmers in their corner and play in other rooms, problem solved!” Well… No. Not at all. You see, as you can imagine, those rigged matches obviously ended up with totally ludicrous scores, kill counts and KDR for the vehicle used, thus feeding the Almighty Statistics™ with flawed data. Given the overall restricted number of SIM mode players, the sheer amount of farming turned out to be enough to alter the perceived (from Gaijin’s pov) efficiency of vehicles, by a wide margin.
As a result, despite the complains from regular players, “economy balancing” patches started coming, progressively nerfing rewards for sim mode, down to a point where the mode became a massive currency sink with little to no reward for playing, UNLESS deliberately farming!
Dudes at Gaijin were like:
-Hey Ivan, looks like the average rewards in SIM are really high!
-Da, I know, it’s because some farmers exploit the system to progress faster.
-That’s no good, we CAN’T absolutely allow people to progress fast!
-So should we, like, think of a way to prevent abuse?
-Nyet, too hard. Just nerf SIM earnings to the ground and raise costs sky-high, so not even abusers will be able to progress fast.
-That’s genius! But… Won’t normal SIM players complain?
-Who cares, there’s barely any of them.
-You’re right, xaxaxaxa!
TLDR: if the custom lobby system is to provide XP and bronze rewards, it better be arranged in order to prevent the creation of deliberately unbalanced or one-sided matches, or else it will be abused to a point that the earnings will be lowered for everybody.