Air BnB's are great in the states for long visits to just about anywhere in foreign countries but for s few days in each city I much prefer hotels, here's why. Hotels provide innumerable services like making restaurant reservations. When I travel I am particular about where I eat and like to make a reservation at least a week or two before I arrive.
So if I am in Naples and going to Rome I will give the desk clerk at my hotel a list of the restaurants at which I choose to dine including the name, phone number, number of people, date and time I would like to go as well as if I am flexible. I am not going to suffer for nine hours on a flight to pick a random place to eat and only have a bad story with which to come home!
Hotels can easily arrange to have your laundry done, typically there is no premium on laundry services in Italy and it is back the next day. If you are traveling for two weekend traveling to three cities you literally only need a 5-6 day supply of clothes. Pack lightly, you will be carrying your luggage and lugging it on and off trains and in some cases up and down stairs.
Even three star hotels will call taxi cabs for you, arrange theater and tour tickets and help you get to ferries as well as trains and airports.
You'll have fresh towels and linens. Most Air BnB's in Italy will have washer/dryers many all in one but trust me I may take your entire vacation to wash a piar of socks in one of these one gallon washer dryers.
The safety factor is huge. At hotels there will be someone there when you arrive that is not going to rob you! You will have a safe to leave your valuables, extra cash, jewelry and documents. Your laptop or iPad can fit in the safe. It is likely your hotel will be in a safe neighborhood that you can get to and from most times of day. Recently a friend sent me a map showing the location of an Air BnB her friend had reserved and it was it a place I know to be very sketchy. Your safety is worth a few extra dollars if it even cost a few dollars more.
Agriturismo's are a different story and I'll talk about them in another post.