An OS that has objectively less functionality, less stability and less battery life (probably less security, too) than what’s available via libre(-ish) alternatives doesn’t strike me as something anyone would want to have, at least while these alternatives still receive relevant feature and security updates.
If Nura is ever able to close this gap, that changes of course. For now I don’t see the appeal.

On a 10 year old phone that can’t/shouldn’t be used for anything else that’s different, however. I’m glad to get a use out of that phone with Nura if the alternative is for it to be e-waste.