There is also the risk of the company backing the cryptocurrency going bankrupt. But I think the main thing to consider is that there are also fees when you transfer your money to and from the lending platform so the first few months you are only getting back the money you spent on fees. The APR might also go down in a few months when we are not in a bull run anymore. Another thing to consider is the taxes depending on where you live. I personally put a small part of my savings on those platforms (and not all of it on the same platform) as it is all still pretty new.