Anki is unbeatable for acing any test with a bounded number of questions [1]. It's been successfully used by some top TV show contestants to remember thousands of words [2].
I've been using it recently to remember recipes and cooking facts, such as the time it takes to boil X vegetable, or the ingredients for some dish.
Apart from language learning and medicine, there's a lack of pre-built decks that you can use to learn topics. I'm building Python.cards [3] to apply spaced repetition to learn Python with pre-built decks, daily reminders, etc. to make it the most convenient.
When Anki is the right tool for the job, it is amazing. I used it to study the questions for the FCC radio amateur license. Pre-made decks were available, so I just loaded it and studied on my phone when I had free time. I had around 2 months before the test, so it was very pleasant to slowly go through all the questions.
It seems the tricky part is motivation. Very few people get excited by card-reviewing itself. The method shines when there is external pressure, such as exams.
I think a sense of community can help provide this motivation (like a group of people all learning at the same time), but it's still tricky.