Did you find that it wasn't beneficial? Cause for me that action is minimizing risks. I never use all moments, I only try and aim to use best ones or sometimes good ones and never judge myself for my actions when I profit by saying that if I wait a little more, I would profit much.
But I see what's your point, usually altcoins follow to bitcoin but there are some that are independent from it and that's a good moment. I wouldn't say it minimizes the risk but probably the profit you may get from one altcoin won't be high enough to cover bitcoin's loss and opposite.
It's hard task, I may do some research on that, worth to keep an eye on.