Everything is dangerous and risky... But knives and knife fighting, is much more common than sword fighting. Knowing about it makes you slightly safer. Such as, hats and coats can be used as Shields, and blade "binders" to give you that extra fraction of a second that you need to survive.
Since, "one stab or slice can really mess you up," wouldn't you rather know how to deliver it, as well as how to avoid it? Instead of ignoring it?
Sure, knife fighting is often a lose lose proposition! The best way to win a knife fight is to avoid one! I count my "wins" as fights where no one got cut and everyone agreed to quit!
Knives and swords are just tools. There are sword dudes on YouTube that say swords were also used to cut wood in Europe! Dual purpose...
Anyway, it's cheaper than guns and more available. Plus i collect knives so it's foolish for me to not know the history and various uses of them.
I also collect antique yard tools. For a while i had a awesome axe collection, but i sold it to help buy my recumbent.