Yeah there's also a terminal emulator built into VS Code, but it seems that every release they add a heap of features to it which I feel like are already present in existing emulators - feels like reinventing the wheel and I'm not sure about the benefits yet.
Besides of course ease in styling with css and hackability.
Hi, I build the terminal in VS Code and am a maintainer on xterm.js. There is some reinventing of the wheel happening but that's because xterm.js is the best option out there for building a terminal in a web context. As WorldMaker mentioned though, it's open source and a communal effort, so anyone can pick it up and build a terminal that runs in a browser or Electron with ease.
VS Code and Hyper both use the same upstream emulator library (xterm.js [1]), so at least a lot of the wheel "reinvention" in this space is a communal effort.
Besides of course ease in styling with css and hackability.