Compile times for the tree I work on range between around 40 minutes (the build VMs at work) and 7 minutes (locally, X-25 SSD, overclocked i7 920, 12GB RAM etc.) There's a huge difference between those two; and even more, my machine is almost perfectly responsive while I'm building.
The things like ad-hoc log file analysis. The compiler I work with can spit out colossal amounts of logs depending on the settings. A bash pipeline is naturally parallelized, and being able to do grep / sed / sort / uniq etc. rollups over the data in say 4 seconds versus 12 or 20 seconds greatly reduces the chances of breaking flow. A 4 second wait doesn't really tempt you to context switch to another window. 20 or 30 seconds does.
