I sometimes pick up my housemate's 3/4 sized spanish guitar and try to remember my chords.
I don't like his steel strung acoustic but the spanish guitar is nylon strung and comfortable. You're right, it's not a bad thing to do at all. It always helps with the main instrument in some way like you say. The ukes are okay too as long as I don't go far from first position.
But, bass is so much more suited to my fat fingers. It's like slipping back into a comfy jock strap after a couple of days of wearing a thong. (Probably should've just thought that too.)