There are many players who play without a strategy, they just choose several teams that they unite in a parley, to get a good odds, this is their entire strategy. There are no strategies for slots, I don’t know what strategies can be applied there. Trading is a completely different matter, there are trends, support and resistance levels from which you can build your actions, in gambling everything is different.
Of cause, there are lots of sys to place your games in gambling. Most Gamblers loves to bet on good players only and make sure their games have greater odds of winning, I guess that might be some strategy of placing bets. Slots don't have any strategy, you just place your bets and let the system do it's thing. If you are lucky, you come out winner and if you not, you end up losing your money. Strategy isn't fisible when it comes to gambling. You just need to play your game hope you have a win.