The problem is that the UX with a browser extension is so much better.
Importantly IMO is the extra phishing protection that the UX is really nice if and only if the url matches what's expected. If you end up on a fake url somehow, it's a nice speed bump that it doesn't let you auto-fill to make you think, hold on, something is wrong here.
If you're used to the clunkier workflow of copy-pasting from a separate app, then it's much easier to absent-mindedly repeat it for a not-quite-right url.
> The problem is that the UX with a browser extension is so much better.
It's better, but calling it so much better [that it's unreasonable to forgo the browser extension] is a bit silly to me.
1. Go to website login page
2. trigger the global shortcut that will invoke your password manager
3. Your password manager will appear with the correct entry usually preselected, if not type 3 letters of the site's name.
4. Press enter to perform the auto type sequence.
There, an entire class of exploits entirely avoided. No more injecting third party JS in all pages. No more keeping an listening socket in your password manager, ready to give away all your secrets.
The tradeoff? You now have to manually press ctrl+shift+space or whatever instead when you need to log in.
The 1Password mobile and desktop apps have such a nice UX that I’m happy copy pasting from and into it instead of having any of the browser extensions enabled.
I have 1Password configured to require password to unlock once per 24 hours. Rest of the time I have it running in the background or unlock it with TouchID (on the MacBook Pro) or FaceID (on the iPhone).
It also helps that I don’t really sign into a ton of services all the time. Mostly I log into HN, and GitHub, and a couple of others. A lot of my usage of 1Password is also centered around other kinds of passwords, like passwords that I use to protect some SSH keys, and passwords for the disk encryption of external hard drives, etc.
Also, you want to avoid exposing your passwords through the clipboard as much as possible.
I also find it far easier to resist accidentally entering credentials in a phishing site... I'm pretty good about checking, but it's something I tend to point out to family and friends to triple check if it doesn't auto suggest the right site.