One of the big reasons I started learning vanilla JS a decade ago, and then started evangelizing it to anyone who would listen, is because it’s so much better for performance than using libraries and frameworks.
Libraries can be awesome, and definitely have their place. I use a few myself.
If you work on modern device with a fast internet connection, you might not notice. But not everyone does.
This past weekend, I had an experience that really reinforced why Web Performance is so vitally important. We were on vacation in a remote part of coastal Maine. There was limited 3G service, no TV (my kids hated that part), and very slow broadband with limited range wifi … However, when the power briefly went out, the annoyance became a major problem! I couldn’t look up the power company phone number, or go online to report the outage b/c sites loaded so slowly. Luckily the neighbor took care of it, but if they hadn’t been there, we were stuck.
This is not the first story of its kind that I’ve read.