I've got two of them in my garage. Legacies from my childhood when frost formed on the inside of the bedroom windows.
Good points - you could cook on them, they were fitted with a device that snuffed the flame if you tipped them.
Bad point - you woke up with a stinking headache.
That'll be the CO poisoning. As long as you do wake up, don't worry.
They can create a horrible smell of paraffin and make everything drip with condensation.