A bitcoin is a token of exchange and its value is entirely dependent on the willingness of others to exchange it. Quite unlike shares.
There are certainly differences. The main one being the dividend.
There is a story from the stock exchange days about a trader who buys a tin of beans for 50p. His neighbour thinks it sounds nice so buys it for 60p. Someone else buys it off them for 70p. The price goes up until it reaches £50. The winner opens the tin of beans and they are off. Who does he go back to as most of the intermedaries have cleared off?
That can happen in shares as much as bitcoin.