My ex-boss told me about that. I guess the salt in the cans makes
them a little harder that they would be if you cooked the beans yourself. Also, I think they hold up better while shipped if they're "al dente" in the can.
I make hummus about twice a month this way. And, incidentally, while we're talking about the glycemic index here, I recently read that beans make you process sugars and starches better throughout the day, even though they are a starch, themselves.