Yeah, one of the things I find most interesting is the translators, at least for chinese, often translate the native chinese idioms to ones that are more familiar to the reader than the native saying. It's very annoying to me because you lose a lot of "flavor" of the show when they do that. In the beginning, having the machine translation helped a lot for that.
It was also useful to get a better match to actual word order when a line of dialog was split across several subtitles. Nowadays I've improved to the point that I don't use the machine translation much anymore though. But there's a bunch of useful settings in that dialog, expecially related to when you're studying characters vs pinyin in mandarin.
I also sometimes use it to slow down the speed at which people talk on shows when I'm listening to them. For example, slowing down speed to .875 or even .75 is tolerable.