Went through two of these recently. Despite programming for more than a decade since university, I noticed the the unusual stress level and awkward situation (coding on google docs or a plain editor with no debugging ability) while the interviewer is umming and aahing (way to be judged) while you're thinking your way through a problem with stops and starts. I managed to solve all the problems given, but failed to get past the phone interview without the any feedback as to why. Thinking retrospectively, I'm almost never in that situation and pair programming with real tools and problems is not approximated at all by these types of phone or hangout screens. Neither are the time based coding tests like codility. That being said, the big software companies spend lots of money and time on hiring and swear by this process, so we're in a "like it or leave it" situation.