The point of using frameworks is to take advantage of complex code written by others that’s also well tested. This makes implementing common tasks faster, simpler, and less error prone.

I have a webpage for my wife that has one form to submit they sends an email to her. I used plain JS. It took longer than I thought to implement because I had to reinvent the wheel, so to speak. I had to write everything from scratch.

For a business where the website is changing frequently with many developers, being able to leverage a plethora of existing code and solutions is very helpful.

Heck, even for people writing plain JS, I bet you find yourself writing helper functions and small libraries to DRY you code and make common things easier. Framework invented!