The only difference between a speculator and a physical player is that a speculator generally won't have an interest in having a physical supply or delivery of oil. A speculator is there to invest in the price of oil. And you need to have investment opportunities in oil or the market just won't trade. So a speculator will be buying oil today, based on the expectation of his understanding of the market fundamentals and his analysis of economic factors and IEA statistics, that if he buys today he will have the chance to sell tomorrow at a higher price. That is no different from someone investing in stocks and shares.
Investor is a far better word.
Think of all the corporate banks around the world which have invested in equities, gold or silver on the basis that they hope to get a return. That is what we are all in business to do - to get a return on our investment. A speculator is just someone who is willing to invest in oil as a commodity. I think it is essential. If you go to any oil company operating in the Gulf they will have the price of IPE somewhere on a Reuters screen or a Telerate screen or a Knight Ridder screen or Bloomberg.