Why yes, as a matter of fact, they were --- the unit of discourse in
your typical mainframe customer service app is a screen that gets
shipped as a unit, complete with notations of where the input spaces
are on the screen. The user fills this out, and then the contents of
all the fields are sent back to the mainframe as a unit, after which
the user is presented with the next screen.
IBM originally did this, about 25 years ago, so they could offload the
keystroke-by-keystroke input processing from their mainframes onto
smaller local hardware ("3270 cluster controllers", if I recall the
lingo right). However, it does have the effect of making those
applications a great deal easier to screen-scrape than equivalent uses
of, say, vt100s.