The processing of the device is simple, as are the materials. I would imagine that the device makes any sense if transitionally no oven is available, only then would be in my view a microwave somehow obvious. It is actually possible to cook with it to fry and jaw fun does not make it and the results are okay but not great.
From me there is no real buy recommendation for the device. There are devices on the same principle with better handling, but is several times more expensive. Who transitionally a Behelfsofen wants and has only a small budget for can be accessed here. All others I recommend to consider the alternatives.