Also notice the distortion in the 40x loupe while it is just matching the 10x loupe in power.
Absolutely. A good quality optic is a joy to use. Once you have done so, using anything less is grating.
And re: magnification required to attain edge perfection - no such thing. The edge will never be perfect. Satisfy yourself with excellent. The magnification required to get there is different for everyone. For some of us it's none. For some of us it's as much as we can get. For the rest, somewhere in the middle. Although I enjoy using magnification and find it a very useful tool, I don't need it. The shave is always the final arbiter. Speaking for myself, however, of course I will absolutely use it if it's available.