Swing trading, easy or dangerous?

Today, I saw a post on twitter about a professional swing trader. This guy has been swing trading between altcoins and Bitcoin for over three years now, and says he had made millions.
I am not so sure about those millions, but I am sure it can be a very profitable activity. Even when markets are in a bear run. But patience is key and greed is bad, very bad.

Strategy

His strategy is quite simple. He searches the market for altcoins with good liquidity, for him that is at least a million USD trading volume per day. On which I can follow him. There is no way in pursuing this kind of action, if you don't have the possibility to off load your bags, when things turn out the wrong way. Especially when your working with big money.
The second important parameter in his action is searching for altcoins that have dropped more than others in a certain timeframe. For instance, imagine Hive dropping 20 % when other alts have just dropped ten. And of course, he always checks out if there is no specific reason for that drop. Then he joins in, sells Bitcoin for the specific altcoin and sells when it has risen or dropped 10 %. No matter what happens, no emotion can come in the way of his actions. Sell when you have got your 10 %, sell when you lose 10 %.

He says this activity has been very profitable for him, and I believe that if you follow these basic rules, it can work out pretty well.

Anyone here doing the same? Or something comparable? I am very interested in your strategies!

Sincerely,

Pele23