It sucks that this is the state of things, because of the technical infrastructure that's supporting these systems. But it's absolutely not being advocated because it's technically more efficient, because it's cute for branding, because it helps the marketing team collect customer data. It's entirely based on being able to provide the highest level of consistent service to a customer.
Doing it any other way is prioritizing brand over customer.
It doesn't just suck, it's bad for almost everyone.
> Should I redirect no-www to www?
My guy reaction is still no, fix the technology that was never designed for this mass consumer use. DNS could support cnames for naked domains, but the standard groups only care about backward compatibility and 0-risk, while consumers still don't understand how DNS works at all, and now we have developers who apparently need articles spoon feeding them why it's bad one way and not another.
Doing it any other way is prioritizing brand over customer.