It seems like it can tick many of the boxes for effective long term learning if used properly (including not just surface learning but also deep conceptual understanding). However, my impression is that there is a learning curve and a cost associated to using it consistently, which leads to it not being used as much. Idk. What’s your experience?
It helped me tremendously in college, and I still use it today, both for past knowledge retention, as well as learning some new things. It is an incredible tool.
As far as the learning curve goes, I would recommend this: just use it as is. You can dive down a rabbit hole of optimizing your learning approach and adding the right extensions, but that time is better spent just studying what you want to learn.
Use the Cloze format, keep cards limited to a couple sentences at most, and practice daily for a couple minutes, and you can't go wrong.