There will always be some gadget to fool you into thinking it's making your world safer and easier so you can spend money on it.

Washcloths are much more readily available, come in an endless variety of colour and/or pattern and/or size, and do the job just fine.

Would the silicone nubs feel odd on skin, esp. tender baby skin?

I used to just get into the bathtub with the baby; at least until they were 8 or 9 months or so. They loved floating in a really full tub; I loved just hanging out with them when they were calm.