As far as I know they were getting the feedback from (some) of their bigger customers, and majority of those (most likely US or UK orgs) were asking about help / upcoming support from Alfresco to use this framework. I doubt there was any real technical evaluation of the framework or the most common customer use cases. As best I understand they wanted to go with something considered to be a major standard (so only Angular or React were the major candidates) which would allow customers to build their solutions with any web developers they can readily find on the market, without having to have any special knowledge.
