Teeth are definitely not required equipment when introducing your baby to "real" solid foods, but apparently they are somewhat helpful. Buttercup had no problems for the first 5 months she was eating solids with gumming her food into a pulp and swallowing it. I was amazed at the things she was able to eat, actually! But, having two brand spankin' new teeth has made it possible for her to take proper bites out of food. Although her foods are the same I'm finding that her technique has changed slightly.
The other day I was eating crackers with egg salad while Buttercup ate her lunch of tofu and avocado. I gave her a cracker to see how she'd like it. And...she liked it! I rarely have crackers in the house, since most of them are so salty, processed, refined and trans-fatty, but these happened to be somewhat "healthy" crackers, so I didn't mind sharing them with Buttercup. She didn't mind either. I got a kick out of hearing her little teeth snap the tip of the cracker off. Oh, the things that amuse mothers!
I can definitely see the appeal of crackers as an away-from-home food. They are very portable and easily placate small children. I want to be careful not to rely too heavily on them, since there are lots of other foods that pack a higher nutrition punch.
PROS: very portable
CONS: watch out for non-nutritious filler foods