Non-native apps can be as performant as native ones. I imagine they checked alternatives to Electron and figured a native app would allow them to have better OS integration.
VSCode really stands out to me among Electron apps, which is why I would be really interested in a write up about what they are doing to get it so performant (I think Rust is a part of the answer). Of course you can write terribly performing code on all platforms, but certainly some make it easier and/or have their own performance requirements.
Part of it I think is the super text heavy use case. Unlike slack for isntance that'll have N 30MB gifs (probably multiple copies of each too) in memory at any given point.
And with all the resources of Microsoft behind it still can't compete with something like sublime on performance. I know it makes up for it in other areas like extensibility but I wouldn't describe VSCode as particularly performant.
Have you tried pasting a very long line or huge file into VSCode? I always have Sublime open for these cases where I need to look at a huge JSON file as VSCode just crashes or becomes unusable.
This may be true. However, Electron apps cannot be as performant as native apps can be, which seems to be what they are getting at.