Even though they have a steady income and can gamble, that doesn't mean they can gamble as they please or gamble continuously. because every once in a while when gambling is done responsibly there will definitely be moments of loss of self-control. because they may feel they have a clear income so they dare to gamble using too much money. The temptation that exists in gambling is very strong, even as you say, it can happen.
Yes, quite a few people are tempted by gambling, because basically everyone is tempted by profits like money, who isn't tempted by profitable money? However, what must be remembered is that gambling cannot fully provide benefits, of course this will be problematic if they have too big hopes. If they gamble using all the money they have, it means they have lost self-control and their common sense too and this is what is called an addiction, they can spend a lot of money on gambling that is not clear whether it will give them a win.
A steady income is an advantage for those who gamble because they don't have to worry about allocating their funds. They can manage the allocation of their funds well so that they can gamble at the times they determine. But they really need to control themselves when gambling because many temptations will come when they are gambling. These temptations will tell them to continue gambling without realizing that they have already spent a certain amount of money from their allocated funds, so they should have stopped gambling. They can continue gambling on other days so they don't need to allocate funds for other needs because that could disrupt their finances.
People who are tempted by gambling want to get the fast money that gambling offers but they don't realize that fast money will not always be easy to get. People often have to spend a lot of money before they can win, but unfortunately, the win will not be as big as the amount of money they used to gamble, so they still lose. When they remain unaware of what they are doing, gradually they can become addicted to gambling and that makes them start to forget what they should do when they don't have a schedule to gamble and they will continue to gamble because gambling has become an important thing for them. They are already addicted without them being able to realize it.