It isn’t listed as an Open Source licence which rules it out for most purposes. https://opensource.org/licenses/alphabetical
Upon being asked about this by OSI President Simon Phipps, Kyle Mitchell responded that Blue Oak has no plans to seek approval (https://twitter.com/kemitchell/status/1104579340732264448). I would have found anything else surprising, given that last month Mitchell had this to say about the OSI (in the context of SSPL review):
> I've lost confidence in this body's ability to make rigorous decisions, or even facilitate focused debate, […]. So I've otherwise stopped responding, and focused my efforts where collective time and talent have hope of yielding practical results.
Source: http://lists.opensource.org/pipermail/license-review_lists.o... Context: https://opensource.org/LicenseReview022019