How do you know it is? I would never say Jesus did not walk on water. I merely look for more natural explanations to consider as well. My point is, Jesus walking on water; Jesus turning water into wine; Jesus raising people from the dead; Jesus multiplying loaves and fish have no value and no purpose in my own life. Those events were for people of his time, and good for them. I believe in miracles because I have experienced that myself, so I am the last person to dismiss Biblical miracles as never happening. The miracle in my own life has as little value to anyone else as those miracles have for me. Interesting, but that's all.
However...Jesus' teachings that I can apply in my own life have great value, great purpose.