Hey there! As a long-time 3D user myself I was asking the same question when we were designing the Graph view. We were considering it and decided to omit the idea. First, we look at the functionality of some functions, with weighted tangents it is easier to get better spacing, so you end up using way fewer keys, which is better for performance. Second, we do not want to have endless sub-menus with a lot of functionality that is not useful, the goal is to stay user-friendly and intuitive. The problem you can have with weighted tangents in general is when you retime your animation the curve changes shape and destroys your spacing. For that, we have the Retiming option. Try it out, and see what is your favorite way to preserve the curve when you shuffle your keys around.
