Every so often, I have to print things, sign them, and then scan them.
Average time to print something using CUPS: 2.5 hours. I have to know where my printer is plugged in, edit some configuration files, and then fiddle with a GUI control panel, then a web UI. All these steps are necessary, because all of the functionality is not exposed through one of them. Sometimes, I also have to download a "PPD" file.
Average time to scan something using XSANE: 3 seconds. I plug in my scanner. I click on the picture of the scanner in my menu. I click "scan". It scans.
Congratulations, SANE team. You know how to write software.
Better luck next time, CUPS guys.