Other than some relatively graphical advantages like smooth scrolling or cursor animations, there are some practical benefits of using a GUI:
- They enable you to create mappings with the cmd-key (macOS) or the Windows key, for example
<D-a>forcmd + a. (In the GUI app docs, they are sometimes referred to as logo key or super key.) - Due to being an independent app rather than a TUI, they are somewhat better integrated in the operating system, e.g. by having their own app icon in app switchers. (Though this probably mostly concerns non-Linux operating systems.)
- being an independent app allows for easier integration with other apps, for example when setting up "if app X is frontmost" conditions.