If you have a smart phone with mobile service in Italy, then you have a "pocket wifi" already. Just turn on the Hotspot feature of your phone. A separate "pocket wifi" device uses the same cellular technology (and possibly the same mobile provider your phone might roam onto) as your phone.
But does your phone offer service in Italy at all? Depending on your provider, it may not be cheaper or it may not be more expensive than renting some other device...plus it gives you the full use of your regular phone. I use a Dutch SIM card I bought a few years ago for travel in Italy and use my phone's WiFi hotspot feature as needed. Mine will work in Italy, Switzerland, and France. A SIM card bought in Italy may or may not work in Switzerland.