It is more specifically GUIs like the ones in Minecraft, where a single purpose thing has a 1 Slot GUI that adds more steps to the process than just rightclicking it with the Item I have in my hand anyways.
So instead of 1 click, most operations in a GUI are 3 clicks and 3 Keypresses at minimum. You can probably understand why I dont like GUIs in Minecraft for simple things that dont actually need them.
With my Game I will do something better than that though, likely just “hit context menu key while pointing at thing” -> “open GUI that asks what you wanna process, with a filter to only show things you have in inventory” or “open a GUI with the Recipes you can use with your current Items”. There will be much more variety in accessing Machines and such.