I feel like this is Google's way of trying to take away the bad statistics that a large portion of android phones still run on gingerbread. Almost like phasing out lover level versions and maybe trying to make kit kat the new gingerbread.
Here's a link to what I'm talking about. Android...
I like it, stock messaging (CM10.2) was a bit boring to me. The downside being that I don't actually have anyone to have a conversation with through hangouts because I live in a very iPhone dominate area, so its only an sms app to me.