Last night I gave Little Man a bath. Thinking about some of the comments from fellow moms, I thought, "I totally should try the baby bath tub." So I filled that in the big tub instead and it was great. Not because I used less water (I fear I used more with the rinsing!) but because his ears were water free. It'll work when I bathe him alone. Otherwise, I think we'll continue to use the insert, or more likely, carry him into the shower.
I guess what I was reminded is sometimes it's nice to have the right tool for the job, but often it's not that necessary.