So the pipes in your home are losing heat, and this will be reflected more in the distance the steam has to travel down the pipe. By insulating exposed pipes, they are going to stay warmer for longer periods of time. Steam can then travel faster from the boiler, down the pipes to reach the radiators.
By doing this, it’s going to reduce the time it takes for your heating system to kick in once turned on. And you are increasing the likelihood of heating rooms that are long distances away from the boiler.
Another benefit you’ll find is that it’s going to prevent those annoying leaky pipes, and if you live in colder climates, it’ll definitely help with them freezing over too and would no doubt be a recommended solution for you.
There is a choice of insulation available, and insulating steam pipes needs not be as much a hassle as it seems. It would all depend on whether you are looking for the insulation to blend more with the room you are in, or if you’re not worried about aesthetics at all.
Disregarding aesthetics though, it is a very affordable and achievable method of being more energy efficient and also in the long term it would prove to reduce the amount you spend on your heating to some degree.