Well defenetly winning plays a key role on gambling. If you're just losing how can you call yourself a professional. Atleast you should have the strategy to counterpart your loses. If you're not winning than make sure you can make up those loses in time. But as you said just winning can not define it alone the professionalism. For my point of view, if you can describe why you win and why you lose, make some adjustments and execute you plan according to it. Ig these all fall under professionalism.