And how useful would this information be? srcIP:port_dstIP:port pairs with almost all traffic encrypted. Pretty boring from a sigint pov.

Instagram, YouTube, misc Web traffic, and torrents, with a side of minutae.

I'm certain the three letter agencies yearn for the days before letsencrypt was de facto.

There is the small possibility that the NSA has found cracks in some of the popular cyphers and could actually make sense of the encrypted data. It's not completely out of the question, their cryptanalysis has been shown to be ahead of the public best efforts in the past. They demonstrated it back in the 70s with DES S-boxes hardening them against a technique no one publicly knew about until the 80s.