They’re lightweight, and umm… portable. Portable models normally weigh between 10 and 65 pounds. This makes it easy to move around or take with you on the go.
They're cheaper. The majority cost a fraction of what full size saunas cost.
You don't have to breathe hot air. With most portable units you sit or lie (depending on the model) with your head remaining outside. This is a benefit if breathing in hot air is uncomfortable for you. There are models that include an optional head cover also.
Quicker heating time. Heat up time is about 5 minutes. Full size saunas can take anywhere from 2 to 5 times longer.
Two possible disadvantages come to my mind…
Some people really enjoy the intense heat within the enclosure of a traditional sauna. If you’re one of these people, a portable mini sauna may not feel like a 'real sauna'.
The heat build-up won't compare to regular saunas.
Another possible disadvantage is that the smaller structure may cause some people to feel a bit claustrophobic.
Compact saunas can't quite offer the experience of full size saunas, but...
If your main concern is to receive the health benefits of sauna, then a personal portable sauna is a great option - especially if you want to save space and money.