I've done this as well in the past - worked pretty well with Blink (and a bluetooth Thinkpad keyboard)! Ultimately I missed some functionality, mostly viewing images, which are essential to my workflow, and not available in the terminal. Unfortunately at the time there was no remote desktop tool available for iOS (not sure if one exists now) which would be able to display a GUI client on the iPad through X11 forwarding.
Not sure of Terminal emulator capabilities on Apple devices, but thanks to the Sixel standard [1] and a recent implementation in the form of libsixel [2], several applications, including emacs very much support image output in terminals.