What are the benefits? ... and the setbacks.
No, I wouldnt try it, and I don't see any benefits. Memorizing your seed is risky because people forget stuff all the time. Like sure, some folks have great memories, but most of us will probably mess it up eventually. Instead, I would suggest writing it down and keeping it locked away somewhere secure. That way its there if you need it. But hey if you wanna try using a brain wallet for fun, go for it! Just maybe dont put all your life savings in there if you know your memory isnt perfect. I mean, losing access to your funds would be a major bummer, dont you think?