Gold vs Oil ETC

Does anyone know why the Oil ETCs are affected by rolling yields(selling and buying future contracts when in contango) and the Gold ETCs are not ?

Only info I’ve found is this, does this mean that you don’t have to pay for storage costs and insurance for gold as there’s no steady supply of it like oil… therefore it’s mostly stored in the bank reserves ?

One alternative – the most popular one – is to avoid futures altogether and leave contango at the bus stop. This can be done by buying ETCs that physically hold the actual commodity: “physical ETCs”. This is only feasible and economic for certain commodities, such as precious metals, where holding the commodity is common place and governments do not mind investors hoarding it.