That's putting it in the best possible light. Mining gold leaves the world with physical blocks of gold, which has no continuous upkeep cost. "Mining" cryptocurrency leaves the world with an asset that requires continual upkeep (further "mining") in order to maintain that asset. Any significant drop in the network's hashrate opens it up to attacks.
The upkeep cost for Bitcoin is, and by necessity must be, proportional to the value represented by Bitcoin.
The upkeep cost for Bitcoin is, and by necessity must be, proportional to the value represented by Bitcoin.