If it's working for you, there's no need to change. You're using #Emacs whether it's in the text terminal or in a GUI.
With that said: You're not getting GUI font handling, Emacs access to the range of fonts and sizes, window management and keyboard commands, built-in document and image rendering, pixel-scale sizing of things, etc.
That's what you're missing; whether you want them is up to you. I would advise spending some time making a good config that shows off the GUI, try it on.