The functionality:
This will open a desktop app for you after clicking a link. That is it. This doesn't change the way WebEx in the browser functions (tiling still isn't enabled as the screenshot make it appear, etc.) WebEx is still fairly unusable for Linux users, or Mac/Windows users who don't feel comfortable downloading the WebEx client.

The cost:
Webex can see all of your information on any website, ever. They can read your information when you access your bank accounts. They can read your information when you fill out your tax information. They can read anything, at anytime, and store it how they please.

My take: I don't think this is worth it.