Once assembled the auxiliary handle makes carrying the camera much more pleasant. Although the handle in my opinion is not a must-have because I either way quite "handy" find the m10. But if you have first tried it, you would have to say that it is just super nice (even more so, of course, with large and sometimes heavy lenses).
The extra weight is not worth mentioning.
The price initially seemed not cheap, but the thing is really high-quality workmanship and simply pleasant, so I do not regret the purchase and I recommend to handle anyone who travels a lot with the camera.