He has several lines of business (clothes line, record label, etc.) and he can certainly afford to make unnecessary expenses. But what makes you think that he has a gambling addiction? The fact that he made several bets does not mean anything. Perhaps this is just an advertising campaign or an action to stay in the information field (for him this is the most important business).
I think the gambling that drake did is a business for him. Rich people always think of how to increase their wealth so to be relevant always. No rich person that will depend just on a single job. Drake doesn't depend on rapping alone, he does other businesses like clothing and others. His betting isn't just luck it was a business calculation and that was why he involved lots of money into it.
Sure. Moreover, this is his main main business - to flicker in the information field. He made a few bets and we (as well as many other people) have been discussing this for a long time, and this gives him recognition that can then be monetized through other lines of business. For example, I did not know who he was (at least in such detail) before this news got into the discussion.