For me it depends upon the situation.If the price of alts hits in the market then I will sell my alts and buy bitcoins and save and hold. If the alts I have has high potential in the market I will still hold it and wait for the right time to sell.
In my opinion, what you are saying is the same since if your alts hit in the market, you will be selling them but that also means that you bought it or maybe invested in it right? If that is the case why not just buy Bitcoin directly if that is what you are doing because in your case there will be a time that your alt will also go down and you will lose your investment or profit by buying it.