Ever watch a bartender ring up a complex order? That's a domain where touch exceeds keyboard / mouse hands down. Digital art, such as drawing (or even just whiteboarding an idea).
Too many times to count and I'd disagree it's better than a keyboard equivalent. It's easier for new/casual staff and can be easier for visual people but it's awful compared to someone with a bit of training for complex things. They seem to fail at making the complex things achievable for the less trained as well IME.
Plastering drink logos on big buttons is easy for some, but for non-visual people and those not familiar with the products it's harder/slower than an alphabetical list or typing the first 2 characters. Want to put something on my account? Good luck with the touch keyboard.
Compare those modern touch screen apps to something like a TUI that used to run in the local video shop 30 years ago and there is no comparison in speed and efficiency.
Or a sufficiently complex establishment with a sufficiently trained bartender could do better with keyboard macros. Sure it may be rare but the point is touch interfaces have a complexity limit whereas keyboards and grammars don't.
The answer is agility of thought and execution, and that if you emulate a keyboard on a touch interface as its main interaction paradigm it's to all effects a keyboard, but with less tactile feedback thus harder to get agile with.
There is no one universally great input method.