Messenger for Mac: No modern emoticons?

Messenger for Mac 8 does not use the modern emoticons introduced in Windows Live Wave 3.

This week I finally had the chance to set up my Mac. One of the first applications I installed was Messenger for Mac 8.0.1. Yet I discovered that Messenger for Mac has its own icon set – and old emoticons. All icons except for the buddy icon represent the Wave 3 style still. Have a look yourself:

Why would Messenger for Mac not be up-to-date concerning its emoticons?