Browser security has been high-profile for several years now. When new exploits are discovered or old ones resurface, everyone hears about it. The sheer amount of flaws in IE6 had a big part in how many people switched to alternatives, primarily Firefox. Will tools like this make browsers as a whole more robust?
The more I use a browser, the more I feel like it is becoming an outdated way of communicating with the rest of the world. Just as the type of content demanded by users has changed over time and the services the net offers change, I think the browsers themselves are all due for more than just a facelift – but an overhaul. Perhaps tools like this are an early way of accelerating the process.