The vscode extensions path, unfortunately, would have been too restrictive for many of Scripton's features/technical requirements (tightly coupled REPL, minimal IPC overhead, ...)
This is very frequently mentioned by people when they decide to fork vscode / build their own editor.
Its not a huge deal here (in theory) as this is a python IDE. One of the biggest issues I've seen with other editor forks / whatever is some first party Microsoft extensions (dotnet iirc, cpp) will not function outside Microsoft's vscode release.
Does your editor support vsix extensions? I assume no as you are just using monoco. Again, could be a dealbreaker for many.