A previous poster in this thread,
@Catalin C, could probably answer that as he has asked a question about, what I consider to be, a "collectible" watch.
Anyway, some of my thoughts.
What makes a collector? It depends on the person. Some of us focus on a specific brand, or maybe only chronographs. Like any collector of objects, there are a multitude of choices and variations.
The Omega you posted comes from a period when Omega got caught on the hop by the quartz crisis, among other factors, and their output was nowhere like the quality of the watches from the "Golden days" of vintage Omegas.
Another thing affecting collectibility is the design which is very dated now whereas earlier vintage styles still appeal to the eye.
The integrated case/bracelet is also less desirable as it limits wearing choices.
Again, some integrated case/bracelet watches are highly sought after, but this inn't one of them.
Hang around and explore and you will soon understand the term.