A lot of your points disagree with the very idea of "professionalism", if you're only there for entertainment then you don't need to be professional about it - just have fun. Odds are you'll leave empty handed, so stick to a relatively small and affordable budget, in an extremely rare circumstance you might strike it big. If you're playing at a casino, chances are most of the games have predetermined outcomes based on the level of spending they see within your account, if you're losing thousands per day then it's possible they will throw you a more frequent thousand or even ten thousand win, because they know the psychology that means you will give it all back to them.
I do not think the term professionalism in OP's title means being a profesional gambler but instead, I think it is how a gambler should tackle his gambling activity. Those are the guidlelines to moderate your gambling activity, moderate your losses and moderate your funds while you are engaging gambling activities. It simply give us tips on how we can avoid problems when we gamble.