While I'm happy to hear this announcement, I'm wary still about trusting the Office teams to continue support for this going forward.
Office self-lobotomizes every few cycles - the teams move on and the new inheritors are often not happy with having to continue "legacy" support. Typically they don't understand legacy, so they convince themselves it doesn't matter. They look for any excuse to boneyard the older apps and move onto something they perceive as "strategic" or "cutting edge" with little concern for legacy workflows and documents of their customers. We saw this happen with OneNote once, we can certainly anticipate it happening again. I'd be happier if the Windows 10 app went away (along with all the Universal Windows Platform junk - weren't they killing that platform?) just to focus them on one great application. When MSFT tries to divide it's focus like this it invariably loses focus, and the customer loses productivity.
Of course, the proof will be in the execution of this new statement of support. If there were only an actual name (not just OneNotePM) making that statement!