Can you explain what is the problem in running with the transfer case in 4WD but with the hubs unlocked?

I ask because I have a Ford Ranger with manual hubs and pushbutton transfer case that uses a small motor to shift to 4WD. There is an electrical problem so I can't be sure it will shift when I need it so I've been tempted to just leave it in 4 and lock and unlock the hubs depending on road conditions.

Thanks for any explanation.

------------------