Most people, when you mention the home heating radiator, think of a large metal job, filled with hot water. Though some people like them (there are people who go out of their way to find the antique cast iron radiators as a room feature), most folk would rather do without than have these big things in the home.
The name radiator is just a convenient way of referring to anything that gives off heat by radiation - any hot object (including the people in a room) does this. It is simply that for years the water filled versions were the most common sight in homes and have come to be most closely associated with the name.
These days there is plenty of choice in home heating radiating systems. For those who are not interesting in installing a boiler, there is electric radiant heat. This tends to cost more to run, day to day, than other forms of radiated heat that use hot water, but the differences can be slight. If you do not use a lot of heating then you may find the investment in a hot water system is greater than any saving you will realize over the lifetime of the unit.
Many people with current boiler systems now replace radiators with hot water baseboard heat, which is just as effective but is more attractive and appropriate for the home setting.
For some the ultimate in radiators is to turn the whole floor into one. So-called hydronic radiant floor heat has a lot of die-hard fans, and is certainly worth a look for anyone replacing flooring or building an extension or new home.