I don’t have answers to all of your questions, but I have asked myself the same question. I bought the licence to get this release specifically, and for me it is totally worth it.
I am absolutely nowhere close to a developer, so I wouldn’t be able to say if the release is stable as you intend it, but quite honestly, I have not had any issues with it.
Plus, if there is ever an issue, you can always go back to the previous version, and the community reports (and fixes bug) faster than ever, so you’d be good to go !
Yep - I second that - to this non-developer, it seems absolutely solid. Although I would give a slight warning that I too was equally enthralled by the idea of the canvas, and now I’m on the inside and I have it, I’m not (yet) finding the use cases I had previously envisaged. I am glad however that I’ve finally supported the developers in some way - it’s such beautiful and elegant software, that I’m happy to pay that $25 for what has come before!
I agree with @TheHunch, it was also a way for me to support the Developers.
As per the used case, I am still experimenting myself, and so far, here is what I have found :