I already have Vegas Pro 17

I see. And do you own a "drawing tablet such as a "Wacom Intuos S?"

It will save your peers a lot of unnecessary guesswork if you will but prequalify your own questions.

I have my Bamboo Fun CTE-650. With a steady hand, masks can be created well. The size is just right. However, there could be more programmable buttons. Vegas can also be controlled with the tablet also in parallel with the mouse. Unlike in painting / drawing programs, I see no real benefits, only in masking.

I use the masking tool a lot and wondered if a drawing tablet could do this better and faster than a mouse.

I could see it being useful for surround panning or color wheels, depending on its accuracy vs a mouse.

Generally you set these things up in software to behave like a mouse, unless the software has specific support for these devices (like most imaging software). Most NLEs do not...

A drawing tablet will be more accurate than a mouse, because it's easier to control than a mouse. You'll also be much faster, because of the increased control. But it will still have somewhat of a learning curve (if you're new to them).

Probably easier to do on something like a Surface Pro/Book/Studio than with a Tablet that doesn't have a screen :-P

Too bad Windows 10 doesn't have anything like the Sidecar feature coming to macOS. I'd buy a Surface Go for that :-P

I've got an intuos pro medium, which I don't use enough - mainly because I don't really have a great space to keep it set-up properly all the time, and because once you faff about setting said device up - it becomes quicker (mostly to just sticking with a scroll mouse. On saying that, +1 in regards to a graphics tablet and drawing masks. Wacom graphics tablets also can act as a big touch pad mouse, which is better than a scroll mouse, but it takes time to get use to the change...there is also a 3d pen which you have to purchase separately ugh, but the pen becomes a de-facto 3d mouse. It has a scroll button, as well as the normal two buttons on the side. Depending on the model - the medium has 8 buttons, you have quite a lot of programmable buttons too. As an audio engineer too, I like the tablet for mixing...it's great for drawing in automation changes.

Hope that helps.

would like to hear more experiences from Surface Go users also, either standalone or as a input tablet in conjunction with a 'proper' editing PC...

My experiences with the graphic tablet are rather mixed. It is very suitable for drawing curves and for painting. When it comes to drawing exact points and then making left or right mouse clicks, I prefer to work with the mouse. The pen has side buttons. Pressing these buttons may cause unwanted movement of the stylus. Even if the click happens by putting on the stylus tip, you need a very steady hand.
This problem does not exist with the mouse. Mouse buttons are pressed downside. Thereby, the mouse always stays in position.

Why should a graphic tablet be more accurate than a mouse? I can always position the mouse with pixel precision. If that does not work, something is wrong.
For a relaxed and pixel-precise working with the mouse, I have switched off the acceleration in Windows. Thus, the mouse pointer follows exactly the hand movement and appears where it is expected. Nevertheless, a small pad is sufficient if the mouse is raised when the edge is reached and placed on the other side to continue. 

A simple graphic tablet does not cost much, so everyone can gain their own experience with it. If necessary, then a more expensive tray can still be purchased.