Candidly, that's crap.
If the spec is written well, there will STILL be points where you need to discuss things interactively. Bouncing emails back and forth during a workday is inefficient anyway; it's CRAZY inefficient if the time zones don't overlap, because then you're really only going to get one volley a day.
Sometimes, TALKING is the right answer. If your dev team is working a day that is totally outside the rest of the company's working hours, then somebody is going to be working weird times to have that meeting, and that sucks for somebody. The hassle of setting UP that sort of call means people don't want to do it, and so cans of misunderstanding get kicked down the road.
I'll never hire offshore again, and I won't work in an org that does it.
Please describe in detail what meaningful collaboration even means. The reason why people don’t often explain what it means (especially in threads like this) is because if they actually write it out, they’ll realize how completely unimportant and unnecessary it is.