It could be seen as another step towards Google's long term plan to make the browser the default platform (opens in new tab) for PC gaming. It's also worth pointing out that Firefox has had the same feature for a while now; indeed Google directs you to a Mozilla site to try it out. You should try it, it's called Bananabread and surprisingly good.
Pointer Lock has also been present in older versions of Chrome (back to 16 I think) but had to be enabled in the hidden settings panel (enter 'chrome://flags' in the URL bar).
It's been an awfully long time since there was much of interest to write about between browser releases, especially as Chrome and Firefox tend to release new versions every few weeks.
(Hat tip to Tech Report (opens in new tab) )