The stats regarding 1 v 2 engines and safety generally can be argued in different ways and yes, of course there are other failures that can bring down a helicopter - not least the seat/stick interface.
BUT, in the context of this thread where we are looking at hovering a helicopter for extended periods over obstacles, deep in the HV curve, with people either working directly under or attached to the aircraft - if you only have one engine and it fails, you are going in hard - no matter how good a pilot you are.
If you fly the same profile in a twin, below OEI hover max weight, you will have options and, more importantly, time to safely extricate yourself and protect the workers.
Does it cost more for a twin? yes, of course but the power companies, like oil companies, rely on operators cutting each others throats to get the contract and driving down safety margins to the minimum.