Is your son already eating solid foods? If you are talking about letting your son "explore" foods by playing with them with his hands to get the texture and smell and such...then I guess your approach makes sense.
However, I find that most of the time it's better to put some of the food in the baby's mouth so that he can get a taste of what it is--then that may or may not pique his interest.
My son isn't a huge fan of bananas but he does really like pureed apples. I mix the apples in with his baby rice cereal when I feed him breakfast in the morning.
When we're eating our meals, we give our son a little taste of the different foods we're eating as long as they are not foods a baby shouldn't have (i.e. we avoid honey, fish, dairy...etc.) This way we get a understanding of what our son likes and doesn't. Surprisingly, he likes the taste of lemons and raspberries as well as curry--things we thought he would hate. And he doesn't like peaches, but we thought he would. We have some teething rusks by Heinz that you can buy at any Wellcome store--we let him chew on these but I wouldn't really consider them a "snack" per se.
At seven months, most babies don't usually do very much "self-feeding"--whenever they're given food to "eat" they usually will just play with it and if it happens to end up in their mouth it is mostly by accident.
My son is seven months old and has been eating solid food since he was five months old.