I had the same feeling, especially with no mention of Google Voice, which has offered a similar ability for nearly a decade (within Google and as Grand Central prior to that). I'm sure there are other alternatives also, but there's no excuse for not mentioning Google's longstanding service.
Remember one HUGE disadvantage of Google Voice: for many of us it was never available.
Well it gets a mention after a sizable chunk of article and the service is freeish anyway.