That's why I love Emacs' tramp mode. Run Emacs on my laptop; access any file I can ssh to. Though also keep in mind that if you have an X11 server running on your laptop you can run any X11 client application (say, your favorite editor) on a remote machine and just have it display on your laptop.
X11 over network is not a reasonable alternative to running an app locally which syncs data intelligently. Like e.g. a web based editor, or emacs in tramp mode.
The lag is noticeable and a bad or spotty connection makes it a no go. No way you can tether or work on a train.
OTOH it's very useful for running computationally expensive programs on my relatively powerful VPS while displaying them on my completely underpowered Chromebook.
