Google's notorious "beta" label on their products is a great way for them to receive forgiveness when things go sideways. Unfortunately, the same thing can be a major problem when looking to gain serious market share.
A potential deal with OEM's to have the browser pre-installed could not have gone forward if the product was still in beta -- so Google had to make the hard decision to remove the "beta" parachute.
The question of Chrome's readiness for mass adoption is valid, and answers will vary from person to person. Personally, I've been using it since it was launched with pretty much nothing that turns me off, but I know that's not necessarily what everyone thinks. The noticeable lack of add-on support is one of the items many people who haven't made the switch typically cite. Add-on's like NoScript are almost impossible to live without once a user decides they like it.
Regardless of how ready the browser is for prime-time, this latest move puts them in a good position to take advantage of OEM's. Having Chrome pre-installed on machines will quickly boost its usage stats -- something I'm sure they wouldn't have a problem with.