What you have to lose is your time spend. At least you'll lose time due to the gamification and the ads. Anki is useful for spaced repetition, but setting up a

What you have to lose is your time spend. At least you'll lose time due to the gamification and the ads. Anki is useful for spaced repetition, but setting up a deck is going to take effort and requires knowledge (building a deck is useful by itself though).