Metaphysics has been called rubbish since at least the early 20th century, when famous mathematical physicist and logical positivist philosopher Rudolph Carnap said it was a waste of time. Later empiricist Willard Van Ormand Quine was less dismissive. Yet, the best and brightest of contemporary expressivist philosophers of physics tend to agree with Carnap.
So why bother with metaphysical questions at all? The best and most common response is that physicists — the new arbiters of reality — often develop metaphysical theories and posits. David Wheeler did it (participatory cosmology). John Barrow and Frank Tipler did it (the anthropic cosmological principle.)