I could play roulette 5 times putting my bet on red each time. This could win me a lot of money or lose me a lot of money or come close to even.

If I play roulette 5000 times putting my bet on red each time I will more closely get the result of being down 1-2% as the house advantage dictates.

If I buy and spend bitcoin every day/week for several years the result will be a slow climb as bitcoin is a depreciating currency.

So no, bitcoin is not only suitable as a store of value.