I dont use this type of prototyping, cause its to much to do if you would test some variations of the code - erasing - flashing, four components you need to handle(erase,burn,cartrisge, chip).
the flashcard from lynxman only needs some seconds, including erasing and writing.
If you want to try a demo, i think this cheap way is OK, if you really want effective coding, you need another tool.
Regards Matthias