The test client only plays Seesmic videos at the moment. It doesn't let you record them. Seesmic won't be updating the Twhirl client for everyone until recording is added. That's due in a few weeks. Following that, although it "will take a while," will be a version of Twhirl that lets users show their Twitter, FriendFeed, and Seesmic feeds in one window. That's the version I'm waiting for.
Twhirl was a brilliant acquisition for Seesmic. Not because it makes Seesmic better. Seesmic.com itself is already an attractive and useful site that doesn't really need a desktop client the way Twitter does. Rather, embedding Seesmic support in Twhirl gives the service exposure to all the Twitter users on Thwirl who would likely otherwise never pay attention to it. The real question for me is how any of these services are going to make money, and especially how those revenue plans will be reflected in aggregating clients like Twhirl.