You can code in Notepad in the same way you can eat off the floor with your hands. Using better tools is a nicer experience.
As for performance, when one of the world’s most popular editor runs on Electron, it’s not that hard to see why performance could be an issue when working on large projects on older hardware.
I’ve never personally had an issue with VSCode’s performance, but I’m also fortunate enough to be in a position where I can afford a relatively modern machine. Many others have to make do with what they have, which is why Zed might appeal to them.