Sucks compared to what? I find anki super. It is amazing what other have built for me to use, for free. It is insane value.
In particular, the UX is a mess. It is very hard for a beginner and frankly it feels like you are in an escape room whenever you want to do something new in terms of difficulty.
Once you are over that hump and just internalize its warts, it is AMAZING, but it IS a huge hurdle for a lot of people.