aren't you expecting a little bit too much? Don't get me wrong, its great if you do... but knowing about upcoming encryption standards is imo something a security engineer should be fluent in, not a web developer.
Yes: it helps the developer to learn to code much more defensively - which is a very good thing. But then, that developer has no time to code. Defensively, or otherwise.
(depending on the environment, and management's willingness to invest in infrastructure - yeah, you can really get bogged down in this stuff).
Tuning performance and setting up logging is another matter.
We're talking about the changelog of TLS 1.2 to 1.3, not the general attack vectors for web applications.