Doesn't Google already have a notes app (Keep) and a document app? How about improving the existing products rather than launching something new. This is clearly something that you can add to Keep and remove later if it is a failure.

Google product managers get bonuses for launching new product, not for improving existing products. It really warps their product portfolio and undermines long term support for products. This is why they have launched a series of chat apps and them let each one languish.

If you were a director at google, would you improve another director's project or start a competing project?

I think this simply allows the team to move faster. For example, you only need to build a website, no Android/iOS app.

Product wise, you have more freedom to build the UX around this new technology without concern for legacy use cases.

Why bother adopting the tool when Google invariably kills it off in a few years anyways?

Launching today and closing next week