Why do you think Pushkin chose the gambling room as a backdrop for this story, and is gambling a symbol for life?
Pushkin employs two Russian literary conventions in "The Queen of Spades." He uses the device of employing a Russian character of German descent to symbolize the virtues of prudence, hard work, and the Greek ideal of moderation. Puskin combines this with the opposing device of a Russian who lives to extremes--not by moderation--and is deflected from the path of the golden mean of moderation, thus falling into disaster, which Pushkin ties in with the idea of life being governed by the supernatural and by Fate.
Gambling is a convention often used in many stories about the upper classes in Russia because it has such potential for great or horrific consequences in addition to showing the power of the supernatural and Fate. Other writers have also used the gambling convention as did Robert Louis Stevenson in New Arabian Nights. In these contexts, gambling is a symbol for extremes in life and the vice of immoderate or the lack of humankind's control over life in the face of the supernatural and Fate, thus representing the virtues and vices of life and the vagaries of life--the constituent parts of life--more than "life" itself, which is itself often represented by such things as threads woven on a loom.