Yet the easiest/cheapest solution for MS would be to create small usb-c/surface-mg-connector adapter. Then both advantages would be preseved (even though how often it happens you stumble across your charging cable right? More like 'let's sell overpriced proprietary docking stations no one can use on other devices' approach...)

This is a very interesting development. Unfortunately, I can't understand from this or the source article exactly what such a cable would look like--is it a two-part cable with detachable tip? This exists in several different forms already, if you search on Amazon, for example.

There are several problems with these existing detachable, magnetic USB type-C cables. If the tip is small, it's still never small enough that you wouldn't notice it sticking out of your phone. And the smallest of tips are  A. not reversible or B. don't support data connectivity

There are reversible magnetic type-C cables that do support USB 2.0 but not DisplayPort or TB3, and I believe there are some that support TB3 now, but these are bulky--they not only use 8 pins, but something like 16 pins, just to support reversability.

And none of these different options from different manufacturers are interchangable. Many good type-C chargers do not support swapping out the built-in cable, making them impossible to use with some magnetic tips. Some of these magnetic adapters do have a female-to-magnetic side (and the magnetic-to-male tip) that plugs into a standard type-C cable. But that adds length or forces a 90 degree turn, making the final connection less likely to stay in place sometimes.

And sometimes the magnetic tip sits flush with your device so it's hard to unplug in case you need to use USB 3.0/DP/TB3, and most laptops only have a single type-C port (or multiple type-Cs with no type-A at all) so it's really not convenient to keep it plugged in all the time.

And on top of all that, in some magnetic adapter reviews people explain that if you connect the magnetic connector cocked a little bit it can short out somehow and break entirely. Some complained about breaking their phone or laptop.

So yeah, if Microsoft can make a good implementation, great. That would be surprising coming from a company that did not embrace type-C at all until recently.