The only CLR routine that I have written , that wasnt "hello world", is to call and mail a SSRS report.
Just like cursors and udfs , from what i see anecdotally, CLR routines are again (over)used by non-set based mindset developers.
They do have a place, interestingly in the latest Phil Factor Speed Phreak Challenge a CLR routine is presently top of the leader board. I suspect though, if and when we get a "ROLLING_BALANCE()" function the need will be even less.