Please, don't feed your cat just treats. They are treats and not food for a reason, namely they're not balanced, so even if your cat likes them, it's like feeding a child only sweets.
As for crunchy staff, some cats like it, some don't. There's a not-quite-myth that dry food keeps your cat's teeth in a better condition than wet food. In theory, when a cat crunches on kibble, it scratches the plaque off the teeth, and chewing helps to work the jaws. In reality, it's not quite so. I don't share the mass hysteria that dry food is bad on principle, but it generally has more carbs and less proteins than wet food. Although it depends on particular brands. And then there's the issue with water intake. Cats are originally used to getting most of their water from their food, so they don't feel thirsty as much as we do. So when they eat dry food exclusively, they might not feel the need to drink enough even when their bodies need water, and in the long run it might lead to health problems.
In any way, dry food is easier to manage for us, humans, because it doesn't get spoiled as fast as wet or natural food, and it's generally cheaper than wet/natural (at least where I live). If your kitten likes it, good for you. Just make sure that there's always fresh water available. Personally, I feed my cats wet food twice a day and leave some dry for them when I go to work (12 hours, too long for a cat to go without food).