Ask HN: Why your university/company still use web proxies?

For those IT managers in universities/companies around the world: Let's Encrypt [1] shown that more than 67% of web traffic from Firefox around the world are encrypted (HTTPS), and Google [2] shown that 67 of 100 top sites has already implemented HTTPS.

With this ongoing trend, why your university/company still use web proxies? Why do you think it is still relevant/not relevant anymore? Are there any legitimate web proxy use cases for your university/company? And how do you react with this trend (that more and more HTTP traffic will be encrypted in the future)?

[1]: https://letsencrypt.org/stats/

[2]: https://transparencyreport.google.com/https/top-sites