I'm a huge fan of spaced repetition and Anki. I strongly believe that most people's professional lives would be improved by using it. There is a huge amount of information that falls into the zone of it's needed often enough that not knowing it is a pain, but it's not needed often enough that you would "naturally" remember it. I've yet to find anything else that only takes 10 to 20 minutes a day that has a higher ROI…
It seems to me that pretty much anything has better ROI then 10-20 minutes of pure rote memorization a day. Plus, keeping in 10-20 minutes a day requires separate skill on itself. Anki has a way of taking over and expanding the time it requires.
Maybe your textbooks just don't distribute problems well enough, the curriculum changes drastically such that what you've just learned isn't touched on again before you forget it, or maybe you just don't have the time or material to consistently practice foreign languages for 1-2 hours a day. In these cases, the 10-20 minutes spent reviewing cards serves as a useful crutch in preventing that information being forgotten entirely, which undoes all the time spent trying to learn it in the first place.