>>hylari+(OP)
To me that sounds like claiming Arduino IDE is a "crucial extension". Their website[1] lists a bunch of IDEs where it can be integrated, so I wouldn't call it missing. That said both of these are hobbyist toys to make it more approachable and embedded development was fine long before VSCode, they're in no way "crucial".
[1]: https://docs.platformio.org/en/latest/integration/ide/index....