Travels a good one. Also, it's nice to be able to use personal devices for work stuff. Say you want to read a doc on your iPad or respond to an email on your phone. I totally understand the security perspective though.
Totally depends on circumstance. Senior government officials should almost certainly maintain clear separation. Highly regulated industries that are logging everything as in the current example. But a dogmatic position that no employee should ever intermix personal and work presences just isn't universally the case.