As a microlight flier, I am supposed to stay well clear of clouds and anything that looks like a cloud. Still I know several microlight pilots who do have an artificial horizon installed - "just in case". I do not know if any ever used it "in anger", but it seems to me that I would not spend the money of a "real" AI, but would consider mounting an Android phone running such an application.
Much agree with MJ though: if it is there, it must be included in the instrument scan, and one should know what information to expect from it, and how to use it.