A lot of it was first-mover advantage. It was the first VS Code plugin to provide a lot of the in-place information that it did, and at first it was unobtrusive and just did the one job well. It only started becoming truly annoying when it became a GitKraken product designed to sell more GitKraken products.

Now that VS Code has more of those features built in and there are alternatives the first mover advantage keeps the extension sticky because people don't feel pressure to learn about the built-in features or because people don't want to learn about alternative extensions because "the tool I already know is annoying but is fine".