The choice of Bitcoin in trading is not really profitable based on my experience compared to altcoins but when it comes to investment, we are certain about it. But, we must also understand that trading is not all about choosing coins, it is also all about the use of strategies and perfect timing. Because even if you choose Bitcoin, you will still have no assurance of a profit especially if you don't have deep knowledge about trading. Many people jump into trading with empty knowledge or just say, knowing only the basics - still, they suffer big losses.
You are right that there is no guarantee that a trader will be able to achieve his profit just by selecting Bitcoin. Especially for those short term traders who fall into panic and cannot control their emotions and those traders who don't know much about technical analysis and proper strategy.
Moreover, if the trader has enough patient and only holds Bitcoin for long-term investment, then surely he can earn profits there. Here he doesn't have to fall prey to any scams, and only if he has a good understanding of the security and privacy of using a non-custodial wallet.