Personally, I like them because I can label each one so that I know exactly what color ink is on it, and I store them in a dauber case. They work for me and I love them!
I agree that if you use a lot of ink colors for sponging, this is a smart idea.
I use sepia all the time,,,,,and the occasional pink and blue,,,,,,,that's it. so for me, a regular sponge is a no brainer,,,,,but if you sponge about 20 colors or more on, lol, the sponge daubers and storage box make huge sense!