Its extremely risky though.
Not really, because they pump up the price of their player.
For example....Palermo want to sell Amauri. They might ask for 23m eur but they will never get that cash. The most they can hope for is 18-19m. So instead of selling him for 19m eur, they sell him for 13m (12.8 actually) cash and they get Nocerino and half of Lanzafame. Even if they immediately sell Nocerino and half of Lanzafame, they can get 7m eur at least and the total they get will be 20m eur. More than if they sold him for cash only.
Genoa did it too. They sold Milito and Thiago Motta in package. The final price for those two was 39m eur. In reality (even if it turned out that they were worth it for Inter), Genoa was never gonna get ~40m eur for those two, right? The most they could get was 30m eur.
Instead of selling them for 30m euro they sell them for 15m eur+Bonucci, Acquafresca, Meggiorini, Bolzoni and Fatic. Even if Genoa sold those 5 players at the same moment, they were gonna get more than 15m eur.
It suits both the smaller team and the big team, because for the big team 2,3 or even 5 million don't make much difference, but they can act quickly instead of having to sell 3-4 young players first.
Lazio might want that too. City can give them 20m eur cash. To Juve they can sell him for 25m eur which will be consisted of 10m cash+Giovinco+Ekdal+half of Lanzafame. Lazio will in the end surely end up with more than 20m eur.