Erm....well, battery life may be reduced, then again, it may not.
Practical use would, obviously be for drawing in drawing apps as well as navigation in app's such as Z-brush, Maya etc...thought that was self evident!?!?!?
As I said NO drawing in a drawing app on a screen thats sitting upright in front of you on a hinge, i.e. the way you use a laptop is not ergonomical nor very precise, thus useless.
Do you use your finger on your phone/tablet?
You might use your finger to touch the screen, yes, of course.
I use my finger to touch shortcuts on the keyboard and the trackpad...what's the problem in having another input?
It's not a problem I just don't see how this "taking away your fingers from mouse and keyboard" to touch something on the screen a meter from you is in any way more "time saving" or "convenient" than just hitting a shortcut on the keyboard or klicking some button with the mouse - where my hands rest already anyways.
If the screen folds right back, like the SurfaceBook, then you can put it on a flat surface, or your 'lap'...some may find it uncomfortable some may not.
You are referring to an ultra-book class notebook. I can - to some degree - see your point if we'd be talking about the MBr, if it would fold back, flat and thin as it is, then it would be quite comfy to operate. But I doubt most people would prefer a comparatively bulky Macbook Pro performance notebook folded backwards to an iPad Pro, yet alone think about Apple, they want to sell you a MBP AND an iPadPro.
The OL' 'not professional' argument doesn't stand up does it?
If I were to use this 'hyperthetical touch Mac' to draw a comic or illustrations, make 3D models and get paid for that then it's professional...right?
Ok.
Something to me - being a professional graphics designer and layouter - is "professional" if it is effecitve and efficient, saves me time, thus stress and money. A touch-screen on a MBP doesn't do that. There might be people who have a use-case where such a device would be perfect, I was just stating my personal opinion.
You don't much fancy the idea and have given some pretty weak reasoning as to why not( namely the battery might be less and you, personally, wouldn't have use for it.
...other people would find such a device highly productive and would have use for it.
I responded more detailed and gave more reasoning. Feel free to disagree.