I'm curious as to why God had Moses do this. Why didn't God just do it Himself? After all, Moses really didn't do anything to cause the miracle--it was God's power on display. You can't help but wonder why God chooses to use the "hands" of men and women to carry out His plans. He could so easily do things on His own.
The answer comes a few verses later..."The people believed in the Lord and in His servant Moses." (Exodus 14:31 ESV)
God chose to use Moses for a specific reason--to establish him as a leader among the people. God was setting Moses up to be seen as the leader.
God understands that we need human leadership if we are to progress. In fact, He tells us..."Where there is no vision, the people perish." (Proverbs 29:18 KJV)
The primary role of a leader is to cast vision and help the people pursue it. God understands that we need 'leaders with human skin' if we are move forward in what He desires. That's why He chooses to use men and women to lead His people.
I'm sure God realizes how it's a risky proposition to attempt to work through the hands of a person, and yet He also knows what can be accomplished in a family, group or nation when an individual surrenders to be used in leadership by Him.