I feel, when bitcoin is used for gambling then yes, trading and gambling dont differ much when it comes to earnings. As bitcoin / crypto market is volatile, as long as you hold the coin earned from gambling and trading, the benefits will be more. Yes, there will be pain when Bitcoin earned in bull market winning in gambling and later the value goes down at bearish market.
I think you are confusing between trading and gambling.
With trading, yes you can buy, hold and wait for the profits. Even if you are not an active trader, buying low and selling high will give you good returns (however you may have to wait many months in bearish markets)
On the other hand, gambling is a game that you play and can win and lose instantly. Gambling is more risker than trading and the motive of gambling is not only to earn money but also to have fun in leisure time.