It really amazes me that people keeps using FileZilla or dedicated ftp graphical clients in general. Linux and Windows has built-in graphical clients in file managers, and I don't recall if MacOS Finder has the same.
It sure does, Finder can easily connect to FTP and other network shares with Finder -> Go -> Connect to Server.
Reasons I can think for dedicated graphical clients is the transfer log and the additional controls when connecting to servers. I agree that it's not really necessary unless you have very specific requirements, I guess.
It's not really comparable. The default side-by-side view most of FTP graphical client use is ciritial and almost essential for any semi-serious use with FTP that is beyond just copying a few files.
I do agree that most of people only use FTP for that, so I guess it's sufficient for average user. Protocol support would still be an issue though.
The FTP support in Windows and MacOS has always been terrible.
Windows used to do it through Internet Explorer, and it was very easy to screw up your whole desktop session as soon as there was anything slightly wrong with an FTP connection. It also did not support ftps or sftp, and often would not handle write permissions properly. I’ve not checked recently but if i remember correctly, years ago there were reports that Microsoft would (rightly) remove support at some point (ftp is just a bad and insecure protocol in 2021).
MacOS Finder afaik never had write-permission support for ftp, and overall the experience was similarly poor. I used to run Cyberduck or Transmit if forced to use FTP.
Linux desktops did include decent support for FTP, particularly in KDE Konqueror which had a great plugin architecture; I expect they still do. FileZilla was never popular on Linux anyway.
Last time I used the built-in FTP client in Windows Explorer it was an awful experience (think it was Windows XP). It also does not support SFTP or SCP.
Then you aren't thinking too hard. Most of these GUIs have advanced features that can be quite useful as well as making it easy to set up sites that you would like to keep but don't want to have to remember the entire address of (aka a sites list). So they definitely have their uses if you aren't just a casual ftp/sftp user.
You can keep a list of different FTP connections in FileZilla and easily connect to one or the other. That's why I keep using it (although less and less these past few years as FTP isn't really a thing anymore).
The site manager of a dedicated FTP client can do more than just save an address.
It can save multiple accounts within the same site, have different IPs and auto rotate, have different profiles about speed limit, thread limit, listing method, encodings, default folder to open on both sides, to name a few.
The Finder is a bit rubbish though, for FTP. It never quite works like it should and likes to hang the Finder, if not the whole device, quite frequently. Transmit is brilliant, though.