from a design perspective, consistency is key. light mode is on? then light mode means light mode, and apps should be in light mode.

do you want both your terminal to be dark theme and your gtk apps (including all of the gnome UI) to be light theme at the same time?

do you want settings within every single app in order to change from light mode to dark mode, as opposed to a global toggle that applies to every UI on your computer?

alternatively, is the terminal the only exception to this global toggle, and this design inconsistency by having the default contradict the default of the rest of your desktop environment is your preference?