To me, BTC feels like the only coin that makes total sense and that I can have conviction independent of the price swings. I'm not saying that other coins don't have merit but I can never fully understand their unique value proposition and place in the market long term. I have to buy into their ideas and rely on others to show me their place in the market.
Also, many altcoins seem threatened by competing coins in the long run. Their thesis is agile and will change to capture a larger audience and more dollars. They are dependent on hype stirred up by their communities and individual leaders. You look to a person or group for reassurance that they will succeed. In some groups, you almost have to deny Bitcoin of its value to fully appreciate putting your dollars into an altcoin instead. It's easier to buy altcoins if the community is telling you they're better than Bitcoin. Although, the comparison never seems appropriate.
To me, Bitcoin seems involved in the least amount of scammy activities. It doesn't offer the complexity to allow for the same level of manipulation and opportunistic behavior that many altcoins possess. I don't look at Bitcoin to convince me of anything. I know what I'm holding and don't have to worry if I'm making the right choice.
The allure of altcoins' superior gains seem like a trap to me most time. I often convince myself to buy an altcoin without fully understanding why. With Bitcoin, I understand why. I don't need a hyper pump that offers a brief moment of peak gains. I just need long and slow Bitcoin adoption and supply/demand growth.
For these reason, I don't worry about Bitcoin. I can just hold and, when the market recovers or enters the next bull market, I'm almost guaranteed for BTC to follow along.