It can also screw you over. I was playing a game yesterday, and a Torian colony ship was rushing to colonise a nearby planet. No worries though- my own colony ship was almost complete. I got the planet, with one turn to spare. Then the game crashed (before people jump on me, I'm not complaining, sometimes these things just happen).
I reloaded, and of course this time the Torian colony ship beat me there by one turn. Sure, it's an isolated incident, but it's pretty damn annoying. And it does happen.
And it doesn't stop cheap gaming. I'm pretty sure I could exploit it. If I have killed most of my opponent's ships, for instance, if I save/reload every turn, they aren't ever going to be able to build any new ones. If I build up a big enough fleet of transports beforehand, I can take their entire empire without giving them a chance to retaliate.
There are tons of other ways to stop the scenario you suggested. For instance, you shouldn't be able to load games without either:
A: Quitting the game
B: Waiting for an hour after you made the save
In these cases, if you crash, you can reload (since you will have left the game). You could still 'cheat' as it where by quitting the game and coming back in, but I doubt people would bother, since it would be more effort. The time limit means you can go back to a different game if you wanted to for some reason (say you were switching users).
Besides, if they really care about cheap gaming, why on earth did they include cheat codes? Sure, they are flagged on metaverse (or something, I haven't checked) but in that case why does the production thing affect non-metaverse games?