Neovim builds upon 3 vim, providing a number of features that normal vim does not have. The main things people want from neovim are language servers and better plugins. There are a billion quadrillion million neovim plugins. Writing this I first wrote just “There are a billion neovim plugins” but then I was worried people would not understand it was hyperbole. There are a lot of neovim plugins.
A number of them are really cool
Here are some examples of cool ones: https://github.com/ggandor/leap.nvim https://github.com/echasnovski/mini.nvim https://github.com/ThePrimeagen/harpoon https://github.com/tpope/vim-surround https://github.com/junegunn/fzf.vim https://github.com/github/copilot.vim https://github.com/nvim-telescope/telescope.nvim
If I had never tried helix, I would probably be using neovim right now, and honestly my life would probably be simpler. Neovim has direct integrations with ghosttext, and a billion other things, and I eventually probably will switch to it.