I thought this superficial kind of learning was more due to the necessity of being brief than the conviction that it's the best way to learn about a topic. We really don't have enough time in our lives to acquire an in-depth understanding of very many things.
You can trade learning more things superficially with learning fewer things in but in greater detail, but if you don't want to make a career out of your knowledge (where specialization is best) it seems like either way is fine if you just do it for fun. (Though I agree that specialization probably is more intellectually fulfilling that fact collecting.)
On the other hand, the more sound generalizations you develop, the more connections you're able to make across topics. You can think of it like a form of compression that allows you to acquire a deeper understanding of things than is possible through memorizing the inner workings of various disparate systems. Deep not necessarily implying rich, as would come with heavy exposure to the minutiae as well.
You can trade learning more things superficially with learning fewer things in but in greater detail, but if you don't want to make a career out of your knowledge (where specialization is best) it seems like either way is fine if you just do it for fun. (Though I agree that specialization probably is more intellectually fulfilling that fact collecting.)