What are you talking about?
Get your facts straight.
This is from Apple's website from the Mavericks Apps lists and descriptions and app overviews.
Here is the overview description for Messages.
Messages on the Mac is more than instant messaging. It comes with iMessage, so you can send unlimited messages to anyone on a Mac or an iPhone, iPad, or iPod touch. You can even start a conversation on your Mac and pick it up on your iOS devices. If you want your friends to see when you’ve read their messages, just turn on read receipts. With end-to-end encryption, your messages stay safe and private. You can also send photos, videos, documents, and contacts to a friend or to a group, and see when your message has been delivered and when someone’s typing a reply. And Messages works seamlessly with Yahoo! Messenger and AIM, so you can keep up with conversations any way you like.
No mention of any live video chat features. You can send VIDEOS, but no live video chatting. Big Difference.