Oh man... buying altcoins because Bitcoin is low is just stupid. You have one of the best performing assets in the world at a discount and you want to risk it by buying altcoins that you don't really want, you just buy them because you feel like they can go up more than BTC?
It's like you have a nice piece of land at a discount, buy you buy a piece of swamp because it's cheaper, hoping that someone will pay more for it? Why do people always want to gamble so much with their investments?
I think that the problem lies with the belief that most of them have created in the market by saying that altcoins are more likely to provide the opportunity for them to make profit than bitcoin. Although we all know that bitcoin has a larger market cap and the volatility compared to altcoins is usually less. So, most of them like to get on altcoins when bitcoin is going rough thinking that there is the possibility for them to make up to 10 times and hundred times their profit than when they continue to hold Bitcoin.
But that is very unlikely to happen as most times the outcome wouldn’t be worth it. When you invest in them you might even end up being the one who is losing when the market never increases again. With bitcoin there is every opportunity that the market goes up after the next halving.