Heavenly Cloud for guidance still needs earthly eyes? Numbers 9-12

At the end of chapter ten of Numbers we read the story of the clound and the fire leading Israel. When God wanted them to move He would move the cloud or fire and they were to follow. The "cloud" of course kept them cool in during the day and the "fire" kept them warm at night. However, at the end of chapter ten we read that Moses asked his father-in-law to "be their eyes" on the journey. This begs the question, "Why do you need earthly eyes when you have a heavenly cloud guiding you?" I think the answer is you don't, but you should! God also commanded them in the begging of chapter ten to construct two trumpets for calling the Israelites to order or to battle. God doesn't need horns to do this but He instructed Moses to construct them. God incorporates the earthly to accomplish the heavenly. From the beginning it was so. When He created Adam His answer for Adam's "aloneness" was to create Eve. God was to be Adam's friend and Adam's companion. God was to be Adam's "complete me" person. However, in God's wisdom He created Eve. God uses the earthly to complete the heavenly. God used David with a "sling" to accomplish the victory over a giant. God uses the earthly to complete the heavenly. So, when you and I need wisdom we could rely completely on the "Spirit" of God who knows the mind of God who is Wisdom (1 Corinthians 2). But, we are to ask others and get advice because in a multitude of counselors there is wisdom (Proverbs 24:6). God gives us the heavenly and expects us to incorporate the earthly in that task.