Some misunderstanding here. The Brick has the same web GUI with knobs and buttons as any other firewall-router. These knobs generate XML which you can later view or edit in the Brick.
I just prefer the XML because I’m an old hacker - I can read it, edit it offline, diff it, archive old versions. I’ve even written an XML preprocessor - versions in AWK and in iOS Shortcuts - which processes the XML, takes ifdef-style directives and can be used to convert an FB2700/2900-format file into an FB2500-format one by taking out references to USB/dongle-related elements. XML is for me the absolute killer advantage of the Brick if you have a complex config. But that’s just me.