Hm.... i renewed my CPR and some other certifications this year and we only talked about it. It kinda-sorta makes sense especially since the guidelines were recently changed to focus more on compressions anyway. but yeah... its just one study though so I doubt they'll be changing guidelines any time soon.
I think part of the push for the no-breaths thing comes from the fact that a lot of people forget the breaths:compressions ratio and don't want to perform CPR on someone. Just remembering "keep compressing chest regularly" is a lot easier.
When I did my recert for CPRFPR they told us about the change. It only applies to the basic level. It's easier for untrained people to do chest compressions only. When you add in the compressions the error rate spikes. Breaths and compressions are still better, but only if you do them both properly (and they just changed the ratios too).