They are all the rage because they help you control the weather (a little). If you are worried that the cold is going to be a problem for some function you are planning then perhaps patio heater hire is the answer.
If you are planning a big family gathering - a special birthday, a wedding, engagement party - you might be relying on the guests spending some of their time in the yard, patio or garden. (You might not want fifty people crowded in your kitchen!) In many parts of the country and at many times of year, the weather can put a stop to the outside life by being just unpleasantly cold - all the ladies in their sleeveless dresses...
Needless to say this is where outdoor patio heaters come into their own. They really do combat the cold very effectively - as you can see just by looking at the number of bars and restaurants that are beginning to use them.
The idea of hiring patio heaters begins to make sense if you think you need more than one - most homes will never need more than a single gas patio heater. If, on the other hand, you think one will suffice, then it might make more sense to buy. You do not need to hire one just to test them out - you only need to go for a drink at a place that uses them. If you own one then you and your immediate family can enjoy sitting out when the weather takes a turn towards winter.