The idea of building stuff myself always appeals to me, coding to me is an endless world, and using Nvim as my main editor is one of my favorite hobbies. It's so fun to set up your entire environment from scratch, and once I started, I couldn't stop.
The ability to customize your tools is amazing, and everyone should try it. I won't touch on productivity, because it's too personal, and what works for me may not work for you. Basically, the primary idea of vim's productivity is "keep-your-hands-on-the-keyboard." Sure, that's great for developing and writing/editing texts, but you can get the same feeling when using your favorite code editor if you keep training the shortcuts.
It's awesome to be able to keep my tools and build my work environment the way I want with Nvim.
If you spend most of your day using your tools and enviroments while working or just coding, you should let them take the most part of your production; your brain should only be used to achieve your goals. With Nvim, I increased my productivity and passion for coding, and now I love customizing my tools. That's awesome