I appreciate that this improved the code base quality for Mozilla folks, but it was a significant step down in features for me. I even switched to Vivaldi (which has built-in Vim keybindings) for a while because of this.
[1]: There are some partial replacements, but they all fail if you try commands on a still-loading page, and they don't work at all on any browser page like New Tab or Settings. So even a simple hotkey for "go to left tab", or "close current tab", fails constantly. I didn't stick around to find out what else is broken.