That page says, "Requires Google Chrome or Firefox," and the download link takes you to the Chrome web store. I'm not sure the poster considers that full support.
That's somewhat fair, although the 1Password X page (which is what AgileBits calls their in-browser version) describes it as being comparable to the native versions, which to me goes against OP's statement that
> full functionality can’t be dependent on an app which is only available on Mac OS and/or Windows.
The existence of 1Password X means that full functionality is not _dependent_ on a MacOS/Windows app. The argument that there should be a graphical (because there _is_ a multi-platform CLI), native app for Linux, which does not depend on any browser, is a perfectly valid one -- but it is also an argument that I don't believe they've made.
1Password X is definitely not comparable to the native versions, and the statement was "full functionality can’t be dependent on an app which is only available on Mac OS and/or Windows."
> The argument that there should be a graphical (because there _is_ a multi-platform CLI), native app for Linux, which does not depend on any browser, is a perfectly valid one -- but it is also an argument that I don't believe they've made.
There are applications besides web browsers that require passwords. For example, password-protected documents, or encrypted archives. A password managers that requires, or only supports, web browsers is incomplete.
A password manager that is only usable in a web browser may be annoying to use for non-web-related tasks, but presumably you can just switch to your web browser, open up the password manager, and then search for what you need within it. It's not like the password manager is restricted to only giving you access to the passwords for the current site.
Regardless, 1password X does not provide the full functionality of the native apps, so it's fair to say a Mac or Windows app is required for full functionality anyway.
> full functionality can’t be dependent on an app which is only available on Mac OS and/or Windows.
The existence of 1Password X means that full functionality is not _dependent_ on a MacOS/Windows app. The argument that there should be a graphical (because there _is_ a multi-platform CLI), native app for Linux, which does not depend on any browser, is a perfectly valid one -- but it is also an argument that I don't believe they've made.