GUIs are more discoverable than command lines. Text files are easier to save in version control. So it's common to have a system where the GUI hooks new users

GUIs are more discoverable than command lines. Text files are easier to save in version control. So it's common to have a system where the GUI hooks new users, but they eventually have enough configuration in it that the GUI is no longer a reasonable way to control it all, and they need a way to extract the information in a reasonable format. Hence the reason several Jenkins plugins have evolved to do that.