For casual web browsing, on some sites I find it more efficient to click links directly on the screen instead of using a cursor. A big one for me, pinch to zoom for images/charts/maps is a lot more natural to me on a touchscreen.

Controlling mobile emulators when developing mobile apps can also benefit from a touchscreen.

> I feel like the screen would get dirty.

It does, but I'd just wipe it down occasionally like I do my phone.

I recently used a friend's touchscreen laptop to reinstall Windows on it. The touchscreen was handy to scroll with while we waited for Windows Update to find his touchpad driver, but once that was installed, I don't think I even felt tempted to touch the screen again.