i think that bitcoin is good for investment, but if you want get more you can wait until the price down
We cannot be sure that when price will go down and if you are going to hold it for long term then even current price can be considered as a low price as it will rise in future.
We cant really know the bitcoins price movement on the future. If you invest 1 btc as today you cant still assure yourself to have good profits on the long run. If bitcoin price would rose to $1m then for sure its a good result but if bitcoin would reach only on a small amount then its not ideal to hold for long terms.
I don't see it touching the price in millions in future, and 1 btc will not give you enough profits if you simply keep it idle in wallet, but if you start trading with that amount then it will give you better profits.