Why should you invest in gold bullion coins & bars?

Why is it wise to consider investing in gold bullion coins and bars? Could you elaborate on the benefits and advantages of this type of investment? What sets it apart from other investment options, and why might it be a prudent decision for an investor seeking to diversify their portfolio? Is the gold market stable and reliable, or does it come with its own set of risks? And finally, what factors should an investor consider when deciding whether or not to invest in gold bullion coins and bars?