Yep, could also be those things.

But accounts and bookkeepers all know what QuickBooks is and are quite happy to not have to explain to their clients why they need to spend $75 a month on "KowalaBabyPooPoos" or something equally ludicrous name.

Which is the point which you probably didn't miss in the first place.

In that domain (accounting), the name refers to “doing the books” which probably predates the abacus.

At least there's a meaning of word "book" that matches what it does. So once you learned what it does, you can make a mental note of "ah, those books". Imagine it was named FluffyTurtle instead. Good luck remembering what it does even if you already looked it up 20 times before. And not confusing it with SparklyCamel, which is an inventory manager for plumbers.