Is there any practicality to that funky knife design?
Well, they have serrations on the back that sort of remind me of a sword breaker, but without the hooks. https://en.wikipedia.org/wiki/Parrying_dagger#Swordbreaker In my honest, not at all knowledgeable opinion on this subject, If you look at the thickness of the back, it makes it looks a bit more durable for using the dull side to parry attacks.
Or the serrations might just just be ornamental, and it's only thick so it's weight is balanced in a way that it can be thrown better. Never done knife throwing, so I can't say much about that unfortunatly.
Is there any practicality to that funky knife design?
It doesn't show in the illustration, but the knives are fold-out hunting knives. Hikage-chan keeps them all attached to her leather sleeves and whips them out. I feel like the big one's blade folds into itself as well, but it's been awhile. As for the serrations, they're "jimps" common on the backs of hunting knives to prevent the fingers from slipping during use.
Actually, they're not to keep your fingers from slipping. You're more likely to get your fingers wrecked if you use it with that thought in mind.
It's a saw. You use it to saw off small branches for tinder. The original design was used in the survival knife for combat airmen to cut their way out of their downed helicopters. Well, the saw edge won't hold up against thick branches or metal, but it's plenty useful for small scale sawing in a survival scenario.