A lot of Fusion 360 users go for it because of the 3D design/modeling capability that ties directly into CNC and 3D Printing. It's really cost effective for that for hobbyists where they don't have the ability to afford products like SolidWorks and Rhino, etc. I don't really think it's intended for "traditional" dimensioned drawings, but I do agree that it would be nice if dimensions could flow with 3D/three axis drawings like they can in SketchUp.
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The most expensive tool is the one you buy "cheaply" and often...