system
A chat on subreddit /r/wallstreetbets
human
It depends on the product.  
  
 Crude Oil futures price is a benchmark and decent physical trading is trading based on that (with a basis). 
  
 For grains like wheat; not so much. Not so sure about silver tho

gpt
The only thing that depends on the product is how strong the relationship is. If futures are a lot higher than spot, you sell futures and buy the actual commodity and hold until delivery. The most the spread can possibly be is the cost of holding until delivery otherwise an arb sets up. The relationship isn't as strong the other way, but if futures are very low then the spread would be the cost of going without until delivery.