It's not a revolutionary thing - it's a better use for a row of function keys that are already doubled up in what they're designed to do. The touch bar for me has been:
An easier way to do equations - multiply, divide, etc keys that don't really exist are right there on the bar.
I also have Do Not Disturb right on the system buttons side, so instead of having to swipe right to open notification center, move the mouse over, "push" the scroll down to reveal the DND switch and then click it, I just slap the moon button that's always on the keyboard now and boom, I'm in Do Not Disturb mode.
In text fields like this MacRumors one, the formatting bar is now right where my fingers are while typing. Bold, Italics, Underline, Colors, it's a million times easier than having to stop, find the tool I want with the mouse, enable it, continue typing, disable it, and then continue. Sure, there are some keyboard commands for things like bold and italics, but when it's now essentially a key it's faster to have multiple methods of achieving it - and there are no keyboard commands AFAIK for immediate selection of colors as quickly as I was able to do above.
Touch ID is amazing - it works to give admin permission to an app, lock/unlock system preferences panes, etc. Also a time saver.
FCPX's timeline-at-a-glance view is also pretty great on the touch bar. It's a fast way to understand what your timeline looks like from beginning to end as you work on specific portions of it, and lets you navigate it fast, simultaneously with your "keyboard" hand while your trackpad hand doesn't let up and is still navigating.
It's little benefits here and there that make the Touch Bar great. I'm sure it'll be expanded further beyond this, too.