I agree, but I think they may prove to be valuable for learning/ experimenting for cheap. As I said I may try something like this until decide what I would want for more studio type lighting- if I decide to go that route, and also have time to gather funds. Right now I am concentrating on a new (used) body and then I will start to collect better glass, then think about maybe some lighting.
I'm no portrait pro or anything, but do you really think that something like say 1/60 is too slow for still portraits. I personally haven't noticed that that is the case, but maybe you have? I would assume that is where you would want to start and would hope that in that range you would see more consistency from these lights if there is an issue. Again though, this used to be an issue and maybe the flickering isn't even an issue anymore.
You obviously won't get the light output from these that studio strobes would provide, but I think I may try this anyway. I have seen cfl's and tube florescents being used in hot light kits sold, but I doubt that they are any better than something you could fabricate yourself.