I float stuff all the time. Yeah it doesn't look as good, but if it's going to take waay too much time to model in, or get messy, than float it. Also, if u float stuff, it makes it alot faster/easier to just remove some edge looks in your HP model and then you have your LP model ready to Unwrap.
Man, i have my questions about this too...i think if ur gonna bake them into a normal map, it should be fine. But for a high rez model that will be on a movie, can u still use them there? i guess u would still need to bake into a texture, right? To float or not to float!
End result is all that matters, anyone who knows enough to be worthy of you caring of their opinion will know that using floaters well shows you have the technical knowhow to create good results while managing your time properly. Excessively complex meshes only show you're not very good at managing your time, or that…