The motives for Soros, Paulson etc buying Gold ETF`s may be numerous. I have read articles on how the ETF`s have taken a huge slice of investment money that would have been destined for Gold shares, and that my be one of the reasons that they are languishing.
It is doubtful that many of the ETF`s actually physically hold the Gold they have on there books so are in fact a Leverage on Gold. GLD and SLV the two majors fall into that category. In fact I think it is GLD that will not deliver your gold unless you have a large amount, and will only settle in the useless fiat.
Anyway the ETf`s are very easy to get in to and out of with just a click of a mouse and this would be a major consideration of any hedge fund to keep ahead of or to make the market, essential when you have billions in investors money to make returns on.