Keep in mind that this works during the time the market is stable, as in the BTC price remains almost intact as the day before. When the BTC price drops the market crashes down heavily and if you have just bought it with this trade tactic you will end up in a huge loss. Unfortunately the other way ends up the same, when BTC rises it does not mean the alt coins rises as well, most of the time they drop in BTC value while maintaining their dollar value. Only later on they start catching up but just slightly. As an example take the alt coin WAVES, when BTC was close to $3k it was sitting at a price of 250k satoshi, after BTC rose and kept on rising tremendously it went all the way to 35k satoshi while maintaining the same dollar value as it had when it was 250k satoshi. So keep this in mind when applying the trade tactic shown here.