The easiest way to replicate the Greed and Fear model portfolio is by using the autotrading facility. There's a section that explains how that all works. But there can also be good reasons not to use autotrading.
For instance, the trading platform of the investor can not be connected to the autotrading platform. For autotrading to work, there's a somewhat complex set up to go through and not everyone may like this or find it difficult to understand. And for some, it just does not apply. The autotrading construction is something most financial regulators aren't really fond of and as a result, some brokerage firms want to stay away from it. They don't want to risk their good reputation over their clients' portfolios getting destroyed by a bad autotrading trader.
Also, as an investor, you may feel uncomfortable giving the trader full control more or less. If the trader suddenly does weird things, those same actions will take place in the investors' brokerage account instantly. Of course, an investor can always disconnect but the damage may already be done.
And lastly, let's not forget about costs. Both the trader as well as the investor have to pay significant amounts of money to the autotrading platform. Usually, both parties have to be subscribed to some program of the autotrading platform to be connected in the first place and manage or follow a trading strategy. Then the investor, of course, has to pay a certain monthly fee to the trader to copy the trades. But very often, some 50% of this fee goes to the autotrading platform as well. So the trader has to perform pretty well, just to cover all these costs in the first place.
If that all sounds familiar, have a look a the other option: the trading signal service.