We are full-time nomads; generally stay 2-3 or more weeks in a location.
We loved Venice; will return!
The flat: Great for short stay; not good for long stay. Simply not enough room and - to be honest - accessories.
You need a microwave, a full size or at least a much larger refrigerator, proper set of pots and pans and cutlery, a set of carving knives, and a comfortable sitting area.
When you stay someplace for a couple of weeks you are a traveler; not a tourist. You like a place that you can relax and watch television; work on your computer. I had to create a place to do that.