First of all, someone who doesn't have a steady source of income cannot gamble in moderation, the like money set apart for gambling can get exhausted and the waits for the next inflow to see another set of funds apart for gambling. Its very irrational for you to dip your hand in your business money to fund your gambling habits. Doing that is a visible indication of addiction. In business, there's capital and profits, when he's harming his capital, then there's serious trouble looming and funny enough most businessmen don't even get very accountable to separate the two, they put everything together and that leads to tampering with your capital unknowingly. When my gambling budget for the week is exhausted, I avoid the casino totally and don't even visit the website to avoid having any form of mixed feelings until I get some fresh funds. Although sometimes as human beings we tend to breach our disciplines unintentionally or when emotions tend to take over us temporarily, but the option for recovery and resetting is more open for someone with a source of income than a jobless person who's making a living from gambling.
Gambling profits are unplanned cashouts and the gambler has the choice to spend his funds in which means he deems necessary, but myself will advise that the gambler takes inventory of himself and spends his Lucky money on something worthwhile just like OP did or divert it to upgrading his business or making a good investment. It gives joy when you can point out to something as an achievement from a certain activity. Although I frown at buying unnecessary things too.
I disagree with this (Depending what you mean by steady income). You can almost always play with moderation, but you just need to moderate it more and play with the fraction of money you would otherwise play with. And since you don't do that for living anyway, but for fun. So bets don't need to be high. I would however plan and budget ahead at least to next confimed paycheck before doing that.
If that income is so unsteady that there's no way of knowing if i am ever going to get that paycheck, then i agree that i wouldn't gamble during that time. Because planning would be hard even without extra expenses. Main things should always be rent, food, water and electricity bills. Everything else is secondary, at least to me. Because without those things working, just surviving daily is exponentially harder.
Again, this would only consider people who gamble for fun. People who gamble for living i do not understand, but luckily i don't have to.