There was a 3rd party software tool (the name of which I forget) that used the same graphics memory as scratch space trick when copying floppies on early 128k (and probably 512k) Macs. This reduced the number of swaps required to copy a 400k floppy.
I think it's more "we only have a megabyte of RAM, in some cases we'll just have to use the part the framebuffer is in". The Scavenger (its equivalent of the fsck filesystem checker) did the same thing.
