It's been a while when I've used VS code in production but on Linux the issues with Atom have been less from the very start and VS Code simply never delivered the performance increase everyone was talking about. Maybe because I never made it an IDE but used it as editor.
On Linux Atom simply was the "better" choice for a long time.
Having used Atom and VS Code on an old laptop in college, VS Code definitely does a better job when you throw it a large file, a first-gen i5, and 4GB of RAM. Likewise, at my first internship, I tried sublime on my work computer, which they had clearly just grabbed from the storage room (Windows 7! In 2018!). Sublime exploded into a million pieces.
My point is this: if we're being honest, all Electron-based editors suck. They're slow, and community-provided extensions are buggy and they integrate awkwardly with each other. But in my world (embedded firmware) there simply isn't a less-terrible option. VS Code is the least-terrible among them.
On Linux Atom simply was the "better" choice for a long time.