Why is mantle so important?

Could you please elaborate on the significance of mantle? I'm genuinely curious as to why it holds such a pivotal position. Could you delve deeper into its role and impact in the context you've mentioned? I'm eager to understand its underlying importance and how it contributes to the overall picture. It seems to be a crucial component, but I'd appreciate it if you could clarify its significance further. Thank you for your time and expertise in this matter.