I think forcing a team to ask these questions is more important than making the document perfect. I've had too many conversations that amounted to "a React front-end, Node backend, Mondo data store is the perfect solution to this and every problem," with no other options chosen.

There's also value on having some this kind of documentation when you're bringing on new people. The project I'm currently working on started two years before I got here, and I would love to have a document that explained why, for example, we're using Active Directory instead of some other authentication mechanism.