Even Apple is bringing its TV app to more and more other devices / platforms. Weakening their own position by making their own streaming device kind of redundant.

Please correct me if I'm wrong about this, but doesn't the AppleTV+ available app on 3rd party devices only let users stream content from the AppleTV+ subscription service? Or does it work like the Prime Video app in that it also lets you view content from additional services provided that the user has subscribed to those additional services specifically via the appleTV app itself?

Because I've been under the impression that the AppleTV+ app that's currently available on Roku boxes, smart TVs, game consoles, etc. only allows users to watch AppleTV+ content. And if that's right, then making the AppleTV+ app available on Roku boxes does not weaken Apple's position in the streaming device market (just like how being able to watch Prime Video content on an AppleTV box in addition to an Amazon Fire Stick does not weaken Amazon's position in the streaming device market).

Although regardless of me being right or wrong about the above, one thing that certainly is weakening Apple's position in the streaming device market is their bone-headed decision to give their box (AppleTV) and streaming service (AppleTV+) nearly identical names. It has created so much confusion in the marketplace. It's even created confusion in this subreddit which on paper is supposed to be devoted to the box itself, but often seems tons of submissions about AppleTV+ content which can be viewed on numerous streaming devices.