I assume those spots are there at BRU because it's nice not to lug 2 full carts all the way through the parking lot by yourself, PG or otherwise expecting. I didn't really use them when I was PG the first time, but it was a nice option the second time around when I had a toddler in tow. the only time I've looked askance at someone using the toddler/infant marked spots is when it was a 60+ yo old man who was alone and got out of his car barking "Damn it, the best spots in the lot should be open to ANYONE! Grumble grumble grumble."
It's a lot easier in some states than others to get a handicap placard. I think I've read here and on another message board that Ohio is like ridiculously easy to get a hangtag, and people have them for really no good reason, but in other states/municipalities, it's practically impossible to get them.
Our local library has spots up front for "Parents with infants, toddlers and strollers." I have an infant and a toddler but don't use a stroller most of the time we go there. I still use the spot if one's available. It's nice to be a little closer because my toddler is often VERY excited to be there and over-stimulated on the way out and it's just easier to have the car parked close by. But it's also no big deal if they are taken.