https://cointelegraph.com/news/buy-bitcoin-sell-your-altcoins-says-pioneering-wall-street-blockchain-analyst
This is not a strategy but just way of trading your alts. I dont think that buying btc by selling your altcoins means anything at all. I mean it is simple fact that, if you bought your auctions at some point then you bought them with vision of something! Like getting 40% profits out of this portfolio or at least sell the alts when they will be 2x, 5x or etc. If you buy altcoins with that strategy then why even care to sell them for the bitcoin? Always keep both thing separate and do not mix them for any investment. If you see bitcoin has dropped and want to make some investment then do it with additional fiat but not the alts. This wont disturb your investment at all.