Most of the recommendation here is to invest in trading and that is good recommnedation and also investing in gambling bankroll can gives you good profit but make sure that you invest in trusted gambling site. Do not bite if someone offering you higher return and moat of that is a scam.
Trading and gambling is also good but i think current time is very best to hold your bitcoin because you can see that bitcoin price increasing on daily base and someone has no good knowledge about trading or gambling they can hold their bitcoin.
Trading is a good place to invest bitcoins but I completely disagree on gambling part as that is the best place to loose our money in quick time and at this high price of bitcoins we cannot afford to loose even a single penny of it as it takes really hard work and very long time to earn even a small part of bitcoins so I will prefer to stay away from gambling and to make good profits will choose trading over gambling.
i do not know that why many people are against of gambling i think gambling is just for enjoyment but sometime we try to earn some profit but lost and win is depend on our luck we should not blame to gambling because gambling is the way of entertainment and earning money.