Exactly. The Moonswatch didn’t just have the timing and the novelty factor going for it—both of which were huge—but also the fact that pretty much everyone who has even a passing familiarity with watches knows what a Speedmaster is. Probably second only to various Rolex models on the “oh yeah, I’ve heard of that before” familiarity scale. You have to be relatively deep into watches already to know or care what the Fifty Fathoms is — and most of those people probably aren’t the types who will buy a $400 plastic Swatch.
My grandfather was a big outdoorsman, and he specifically left me his rifle and his hunting knife when he died. I am not an outdoorsman, and have zero use for either of these items. I keep them (in a box, in my garage) because they were his, and because it is meaningful to me that he wanted me to have them. But I have no idea if they were expensive or not, if the rifle still works, etc. And I don’t really care.
I also have my grandpa’s old trucker jacket, which he used to wear all the time, and which he probably bought cheap at a Montgomery Ward or something. It’s held up remarkably well, it fits me perfectly, and it actually suits my style quite a bit. And more importantly, I associate this jacket with my grandpa way more than the knife and gun I never saw him use, and it has much more sentimental value to me. I wear it occasionally, and always think of him when I do. My grandpa did not intend to pass this down to me, and probably would be surprised to learn I’ve kept it. But it’s definitely one of those things I would try to save in a fire.
It’s a lovely idea to keep a watch you intend to pass down to your kids, but I don’t know how useful it is to worry about having a watch that’s “worthy” of being an heirloom, or to think about whether it will be affordable to service… It’s at best a coin flip whether it gets worn at all. And the item of yours that actually becomes a part of their life might be something you’d never suspect.