Anything that size will give me arm fatigue using the touch in any meaningful way. For occasional interaction, it's fine, but standing in front of it all day, the touch will mostly get ignored.

After wrangling with some HP TouchSmarts, I agree. The hitboxes suck, the on-screen keyboard is fatiguing after a few sentences, and playing a game with touch only sounds like work.

Eventually you forget that your PC has a touchscreen. Even when you do remember that you can just jab something with your finger, your internal context-switching brain-lobe-thing tells you to not bother because the next few micro-tasks will involve the keyboard and mouse anyway.

Basically, to get the benefit of touch, you have to make it the physical desktop.

I think so. Maybe it all works well on wall-sized touchscreens where you're standing up, but it does not work with vertical glass sitting down.