Bitcoin already proved itself over the years until now. It is a reliable cryptocurrency and the largest blockchain-based digital asset but its price is unstable. Whether you hold for short or long term it is still a risky investment because we aren't sure of its pace.
There are some investors that chooses the short term investment and they earn their money back. I don't get the idea that if I hold and wait for long then bitcoin is considered as a reliable investment? In an investment, there will always be a win or lose and if you lose, that does not make bitcoin a fraud. You just need to be someone who is good at strategy.