They each have their own good and bad points. If you're keeping a baby tortoise, a viv is just fine because you can cover it to keep the warm moist air inside.
I use them for my leopard and YF babies. They're cheap and easy. You can make them work by covering them and lining them to protect the wood and using damp substrate.
Yes you will always need uvb lighting, no matter what type of enclosure you go for. The uv helps them absorb calcium and keeps them from getting metabolic bone disease. Don't forget to change the uv bulbs every 6 months as they lose their efficiency!
No I would not make that blanket statement. What age and size is your hermanni? Where are you?
The closed chamber (Vivarium) method is simply a way to keep the room air out of the tortoise enclosure air. Here in North America the air in most of our houses is too cool and far too dry. Our air conditioners and heaters make it even worse. Even in the humid parts of our country, the indoor air is typically pretty cool and dry. The air in any closed chamber can be kept cool or warm, humid or dry. It just allows a tortoise keeper to control the conditions inside the chamber to make them different than the conditions outside the chamber. If your house is warm and humid all the time, you will not need a closed chamber. You will still need a basking lamp in your indoor set up, and possibly night heat too. Whether or not you need UV depends on your situation and how often your tortoises gets outside for real sunshine. ALL tortoises need a UV source one way or another.