Cool, I appreciate your thoughts. I still disagree, but that only depends on the context. For example, if I have a laptop on my desk or counter my arms are resting on the desk/counter, I'm not lifting my entire arms to touch the screen, just my forearms/hands. If it's on my lap then the touchscreen is even more useful, as the screen being so close really works well and my arms are already supported. I can see your point more on a larger display such as on a full desktop setup. I also think Microsoft has done a very good job of integrating touch into Windows, not perfect by far, but very usable on a surface pro sized screen or above, it always puzzles me when others say it's so difficult.
I can only assume we have differing levels of strength and endurance as I can do this all day long without my arms getting tired in the least. If I don't have a touchscreen and have to use the trackpad all day then I do feel as if I am injuring myself by contorting my hand/wrist all day long, it's a big risk for repetitive stress injuries from an ergonomic perspective and I treat these all day long (same goes for a mouse). Although in reality I use a combination of touch, mouse, a bit of trackpad and keyboard input depending on the context. I suppose I don't really understand how you are using your device where your arms are raised all the time enough to get tired.
Also my apologies if I come across as combative, I definitely respect the way you use your device. I just don't think the entire category of touchscreens should be thrown out in terms of usefulness. Personally I find having a touchscreen incredibly useful, I cannot even begin to list the ways it increases my productivity at work, or just enjoyment when not working. But once again everyone is different.