Best reason to use ftp sites for downloads instead of web servers in decades has been that you the default settings for Apache weren't right for driving a file server-type site. You should just have to configure virtual indexing and server mime types.No good reasons? BS. I serve old Macintosh software to the public via FTP. No login require, nobody is going to give two shi** if it's encrypted or not.
Nobody's requiring you to stop sharing via ftp for pre-browser Macs, remember. You'll just need to provide a website as well for anyone using Firefox (and other browsers going forward).