Anything that helps make diagnosis easier will undoubtedly save games.
For myself, I can do a lot of basic board repairs, but since I don't have a background in electronics or design, some of the low-level stuff that needs a scope and some of the high-level stuff digital stuff is a little beyond me, so good diagnostic tools generally help fill in the gaps. I imagine a lot of pinball enthusiasts like me fall somewhere in the middle.
However, sales for diagnostic tools will probably be limited because you would only sell 1 per customer (rather than a product that needs to be refilled or used once per game), and only a small subset of all zaccaria owners. So, it will probably need to be a labor of love more than something that you will expect to make a hefty profit from.