I need to learn a bit about knife geometry. Why are different knives shaped the way they are ? Especially when you look at the point and the edge geometry seems to have a purpose.

A few days ago I was checking some fixed blade knives and saw one with a "typical" shape, but when touching the edge it was not sharp, rather it was thick !!! Then I realized that it was the other (straight) side that was sharp !! It had a sheath and attached sharpener just like a hunting knife but I dont think it is practical for hunting or camping, or am I wrong ?

I have seen some small elctrician (folding) knives with straight edges, but not a six-inch fixed blade . Isnt that strange ? And what it is used for ?