Some lisp implementation can be run on different architectures.
If users keep the same home on different computers this will lead to collision in ~/.slime/fasl/* directories.
Talking about that, SLIME obviously made his own way to solve this problem. I wonder if you can do that using ASDF? That is, generating fasl file into a "build" directory and not into the root of your project. It's really really annoying. I guess ASDF is enough extensile to do that, but the lack of doc make it difficult to extend.