Although I prefer a call that has some rasp on the backend of a yelp,...which is hard to get (for me anyway) without having some sort of reed cut,...I always carry an assortment of calls that have varying qualities of sound. That way, regardless of the situation I am in, I will be able to produce the sounds that I think are called for in any particular circumstance,...within the limits of my abilities.
I agree that many of us get hung up on trying to achieve that classic duel-tone, "contest caller" yelp when, in reality, that sound is not necessarily what any specific gobbler wants to hear,...and even more certainly is not what every single hen turkey in the woods sounds like when she yelps. Of course, it doesn't hurt to be able to do that but, in my experience, being able to put a call in your mouth that will duplicate just about any hen you might hear in the woods is a good attribute.
Some callers can do that with a single call in their mouths, but I think that is a rare ability for most mouth call users. For most of us, having several calls with varying cuts,...or no cuts,...helps us get the sounds we might need at any given time.