Cuba has four types of plug: type A (two-pin), type B (three-pin), which are both used in the USA and Canada, and type C and type L, which are *not* used in the USA.
The adapter you are looking at allows a two-pin Swiss plug to connect to a type A socket.
Voltage and frequency in Switzerland are 220 V and 50 Hz. In Cuba, they are 110 V/220 V and 60 Hz. Most of the time, it's 110 V, the same as that used in the United States and Canada. But it seems that *some hotels* have 220 V.
So if your appliance is designed to work in the 110 V to 220 V range and can adapt automatically, then all is well.
If your appliance operates at 220 V (check the sticker, the information printed on it or the instructions), you can only use it with this simple adapter in a place that supplies 220 V, i.e. one of the hotels mentioned. If you wish to use a 220 V appliance anywhere else, you will need a transformer with 110 V input and 220 V output.