You make an excellent point there.
the thing that puts me off is there’s quite a bit of jiggery pokery to turn it on…theres a valve thing outside the house would you believe, and you turn that on first.
Which suggests it's a really old one. Efficiency ranges from 60 to 74%, versus a radiant type of around 86%. So using it, you could be just wasting 1/3 of what you pay for gas.
A modern boiler manages around 90% efficiency.