What does that actually mean?
Given that Messages is the default app in iOS for handling texts, if you have not logged in to it, and have no third-party app installed for receiving and handling texts, how would you expect a text to get to your iPhone at all?
I may be rather dumb on this subject, because I'm not much into texting, but I would have expected any third-party texting app to have notification preferences in broadly the same way that Messages does - thus likely able to echo to the watch.