At first it sounds insane that Google would do such a thing since while ad blocking is growing, enabling the feature natively especially by default would incredibly increase the number of ads blocked. My guess is, that where other blockers by default can easily block all google ads, Chrome blocker would not block Google Ads because it would classify them as acceptable. And Google would then hope that people would use…
I like how you see positive in this move, but all I can think of is this. Google will enable ads from google and block everything else. This is their way of killing the competition. I think it is unfair and risky. I don't want google or anybody else deciding what is acceptable ad for me. Even if it is not distracting or passes google's standard of 'good' ad, it should still be my choice that determines if I see it or…
It's not even difficult to do so, by eg. serving pages from a Google-controlled CloudFlare-like proxy service and/or a high-profile Google-style HTML-to-JavaScript encoder. Google's AMP project shows they're willing to throw the decentralized web under the bus.
The real question is: are you ok with ad-financed web sites in general, but have a problem with tracking (like me)? If so, we should really come up with a community-driven criteria for Acceptable Ads, or should disable un-vetted/not-whitelisted JavaScript alltogether.