I am not holding too many altcoins because I don't trust altcoins that much. We have seen some tragic incidents in the past with altcoins, and that has made me vigilant about my investment choices, especially if I'm planning to buy and hold an asset for the long term. I'm mostly invested heavily in Bitcoin, and a few altcoins that I trust the most because I know I can get some profits from them, but I don't want to take too many risks. I know altcoins can be very profitable sometimes, but it's not worth the risks involved, in my opinion.
For me, having most of my capital in Bitcoin, a portion of it in a few top altcoins, and the rest in trading is the best way to move forward. I keep liquid assets that I use for trading activities, and I must say that trading can be very profitable at times if you know how to manage your trades and risk-reward ratio. Don't trade blindly, of course, and make sure you have your stop-losses in place at all times to avoid excessive losses.
To each, their own. Not everyone finds altcoins appaling. Especially when they're much more volatile than Bitcoin and less-decentralized. That's why some people are Bitcoin Maxis. On the other hand, there are people who prefer altcoins instead of Bitcoin out of convenience (low fees, faster confirmation times).
As for me, I'd hold both BTC and altcoins as some sort of diversification strategy to help protect my investment against undesired losses. The more you diversify, the smaller the risk of loss will be. We can never tell when the next "pump" will happen, due to the unpredictability of the crypto market. Just stick with the "blue chip" coins (those among the top ranks in market cap), and there should be nothing to worry about.