There's also plenty of little UX niceties you don't even notice on Chrome, but which are missing on Firefox. Eg. if you create a new bookmarks folder and you add a bookmark to it, this folder stays selected as the default option when you're adding another bookmark. This doesn't happen on Firefox for some reason.
Or, another example off the top of my head: I always customize my browsers so that the next tab gets open right next to the current one - not at the end. There are lightweight extensions for both browsers that accomplish just that. But only on Firefox the new tab jumps back and forth when you open it; opening at the end for a fraction of a second, then bouncing back where I want it. On Chrome it's instantaneous.
Or downloading files: Chrome automatically shows a download bar for an ongoing download, and you can open the freshly downloaded file right from there. Firefox doesn't do it. You have to manually tap a rather discreet arrow icon on the toolbar to open the downloads list. (Which you may even forget to, if we speak of a large download that takes several minutes). Maybe there's some extension for that, but Chrome has this by default.
Translating webpages is another one. There are several extensions available for Firefox, but not one of them comes close to the convenience Chrome offers by default in this regard.
I know a lot these are arguably petty things, but boy is there so many of them. And I think at least the majority of don't really fall into the "matter of taste" category. Chrome simply offers more polished user experience, and while these may be details, at the end of the day all these details add up.