Actually, that might not be clear enough.....
By "Electronics" he means led scoreboards. You know how modern pins have those graphical led displays that support animation, and graphics and what-not? You can't play those tables without pinmame, period, so there is no choice involved. With older games that use a more traditional score board you can get away with just visual pinball. I would like to point out, however, that games made prior to the 70's are only playable without pinmame as they lack any digital electronics.
Not only that but mid era games (pins from the 70's) run either way, and often all the electronics are also "emulated" via script on the visual pinball version. So sometimes the non pinmame version is actually better visually. (70's digital displays look like utter crap in pinmame) A good example is the playboy table. Looks waaay better in it's scripted, visual pinball form.
I hate to complicate a simple answer, but it wasn't completely accurate.
Sorry.
