It is debatable whether that ETF holds as much gold as they are supposed to, as IOUs of gold from other institutions count as "gold" for their accounting (as I understand it.)

This is the real problem we've seen in gold bull markets in the past, and currently the derivatives trade far exceeds the global supply of gold. (And an "IOU" is a derivative)

I'd recommend either holding physical yourself or holding allocated gold on account with a trustworthy depository.

The ETF, however, is probably good if you want to try an option strategy.