I love jjui, but I feel like it's also the reason I still use him over vscode. If you already use vscode, doesn't using a vscode extension make more sense?
Of course there are some people that will want a gui not matter what. Then an extension or separate program is the only thing you can do. But i think it is really nice to have the same tool available everywhere, also in the terminal. And if you want a neat and vertical pane in vscode just drag a new terminal window next to your code and run jjui in it.