I used this to enhance a microsite I made just the other day (https://www.churnratecalculator.com), and it was a snap to integrate (ba-dum psh!).
Used the following guide to set up react-snap into an existing CRA application in just a couple minutes: https://medium.com/superhighfives/an-almost-static-stack-6df...
I want to investigate the CSS inlining feature--that's one of the areas where I still am loading a decently large external resource. Experimental, but could be a nice win.
(Edit: added the guide I used where I originally found out about react-snap)