The difference for some people is security. Owning will always be better if you trust that gold/silver is a worldwide trading currency when and if the world has some sort of economic disaster and your money is worthless, stocks can't get 'cashed out' or even if they could the money again, equals worthless. I have silver coins, however coins cannot be melted thus they sometimes aren't viewed as valuable due to the limitations of not being able to melt them down since they are considered legal currency. I've yet to buy gold/silver bars. I don't think I'll buy gold coins, just bars if I get the spare cash to do so.
I've played NUGT soley because in Canada we have Tax Free Savings accounts which allow us to put money in and have it non taxable, you can play stocks with TFSA accounts. Thus gold stocks/etfs were a no brainer for investing some of my savings.
If you believe that one day you may require real hard physical gold/silver to trade between people in your community due to a economic crisis then stock up on the physical stuff. If you believe the world wont ever come to that point in your country then stick to stocks/etfs
the physical stuff always has premiums, you'll always be paying more for the bar just like when you buy a car, once you take it off the lot it's yours and the value cannot be resold right then and there for the same price. you'll be paying fee's to resell. With stocks/etfs you pay your buy/sell fee's which if you have a decent broker wont be very expensive(my trading fee's are max 9.95 a trade so can buy/sell flip for under $20) which for me is better than having to spend gas money to go to a place to sell my gold/silver and or ship it plus deal with trading fees. Also if you store your gold/silver in a secure location you are paying them per month per ounce to store your stuff - just another thing to consider as you may not want your gold/silver to be stolen if someone were to break into your home etc.
overall for myself I'd rather play with the etfs or stocks. easy to trade, no having to leave the house to sell anything or buy anything. no storage issues. But there is the big risk of a stock/etf tanking and or the economy/country going into some seizure mode like Greece recently did. Then you wont have any investments. sometimes owning what others cannot see is better. Just make sure you store it in a safe place.
If I were you I'd invest some in the physicals and some in the virtuals. keep the physicals for long term investments and virtuals for short term flipping or long term but able to sell off easily.
AI
