The sole purpose of the 3 hour delay is to make it impossible to create dosing apps based on the data. If real time data were available, one could imagine all kinds of “bolus-wizard” type apps popping up in apple and google app stores, which of course could be great, but could also create risks and legal problems for Dex.
Incidentally, Nightscout has had API with real-time access to data for more than 2 years now, which has allowed developments of many watchface apps, analysis tools, etc. It’s fantastic news that Dex is now following the path traced by the DIY community - very smart and courageous! On a related note, the Dexcom team behind the API includes contributors from the #WeAreNotWaiting community, who we should all thank (yet again).