Are all miracles necessary?

I have seriously been thinking since todays lunch time. we have the 'meeting place' which is a religious gathering for chritians every lunch time.

Today we briefly talked about a passage in the bible when Jesus walked on water over to his disciples on the boat, they thought that he was a ghost at first.

It made me think of why did he walk on water. What was the reason for this? It does not say in the bible why he did, for example walk on water? This was a miracle, but it did not make any serious life changing effect for people. Or did it? Did his disciples need the prove to believe in Jesus and all they have heard about him proven. If this is the case then why? we as christians don't need the prove that Jesus performs miracles.

However this was not the only time that Jesus performed miracles in the presence of his disciples, so there have been many experiences where the diciples have seen first hand that Jesus can perfom miracles.

This is not the only question that comes to mind from the story though. If Jesus is able to perform miracles like this (walking on water) which I don't at all dowt he can't. This to me seems such a pointless miracle with no effect of any significance - apart from maybe getting disciples to believe that he is the 'son of God'. If he can do miracles for this reason, then why did he not heal or make more peoples lives affected by miracles. He did perform miracles for good causes (blind bartimaus) that affected this certian person, but surly at this time there would be some christians whov did believe in him but for some reason could not present thiemselfs to jesus, or for some reason did not want to ask? He has the power to perform miracles.

Surly there would be more people like 'Mob'?

I do understand that he can not heal everyone! But for some reason this certain miracle seems some what poinless. however I do undertand that we do not know the full story, there might be a important reason for this miracle.