I've got some growing out back after my third year trying! I wanted the sponges but my wife is bugging me to chop them down to eat. "You people EAT those?!"

Nice life pro tip! Thanks.

but the bristles on those are almost always plastic too, even more inert and probably heavier than sponge of equivalent efficiency.

You also have these with a soap reservoirs built in, you release soap by pressing a button on top of the handle. They're amazing!