iOS Apps on MacOS is a good reason for Apple to incorporate touch screens. Today, they say the trackpad is superior because you aren't raising your hands up to the screen. Touch optimized iOS apps would be a compelling reason to include this feature and motivation for many people to upgrade their MacBooks.
Also, the Microsoft Surface Book Pro has a detachable screen that is a stand alone tablet. What if Apple is designing for an iPad to be the main screen with a base that houses external GPU, battery, keyboard, etc. iPad production ramps up, iPad users can "upgrade" to a full laptop, laptop users are automatically in the iOS eco-system.
I believe it's a T series, though your point still stands. I think I'd personally far prefer a display under the trackpad (though I don't think it's necessary at all) to a TouchBar or a touchscreen laptop. But I think I'm very much in the minority.
Also, the Microsoft Surface Book Pro has a detachable screen that is a stand alone tablet. What if Apple is designing for an iPad to be the main screen with a base that houses external GPU, battery, keyboard, etc. iPad production ramps up, iPad users can "upgrade" to a full laptop, laptop users are automatically in the iOS eco-system.