I'm always amazed when people ship cool software with what I judge to be crappy, obsolete, or even downright dangerous processes/practices. Yet even though I (by my own judgement) use superior processes and practices (VSCode + Git + CI pipelines, etc.), I haven't shipped anything nearly as cool.
A few others that come to mind are KeePass/Dwarf Fortress (no formal VCS), and GRRM (uses WordStar 4.0 in DOS)
I kind of put vscode in the same category as notepad++. Actually, as a text editor, I think N++ has some nice features that vscode doesn't (like macros, I think).
He could have done this just as fast using GIT + CI. VSCode would have likely slowed him down with indexing, and he already knows where all his files are so there wouldn't be any gains from hopping around function declarations with the click of a mouse
Although you didn't pinpoint a single process that was inferior, knowing when to break processes is part of the experience.
A few others that come to mind are KeePass/Dwarf Fortress (no formal VCS), and GRRM (uses WordStar 4.0 in DOS)