Yes I do see your point here, though if you really wanted to you could define just about any word as a "suitcase word".

I think there may be a consensus around a common understanding of mind. IE the thing that controls actions of a "body" <-- pack your bags it's suitcases all the way down ;)

What I find interesting about this idea is that it's an attempt to understand an organism greater than ourselves. It's almost like cells in our own body discussing the nature of the body.