Money and power are two sides of the same coin. Control is the coin. Roth ultimately wanted control. The gold telephone meant little to him since it was just represented another form of currency, a tool, if you will, that would help him achieve control. The business men were impressed with the telephone because it is a novel way of expressing wealth which is what they are pursuing. They don't understand power or control given the limited worlds in which they live in. For them, murder is not really on the table as a way to achieve wealth or control. For Roth and Mike, murder is pretty much a casual instrument.

Maybe we all would like to control everything around us. Roth and Mike wanted to control as much of their environments as they could, but they realized that control has limits. So, they concentrate on what they figure they have the best chance of controlling.