I've tried bouldering in a borrowed pair. Edging gets painful fast. Far too much stress on my toes. Having separated toes and a relatively pliable sole produces an awful lot of foot strain.

Real climbing shoes are tighter and more rigid. They do just the opposite of what these barefoot shoes do; they bunch your toes together, forming them into a kind of single supertoe. It's probably about as bad for you as wearing high-heels, but it's very effective.

Also, the soles on barefoot shoes are not sticky enough for climbing, so smearing doesn't work too well.