I'll rephrase my question. Why do you want to make things better for one of 'you' at the expense of making them worse for many of 'you'?
I thought my answer answered even your rephrased question; I'll try again.
Random events happen in all lives. Some cannot be survived with X resources, but can be survived with Y resources. If you're already above Y, and the cost of a lottery ticket is low enough that it won't bring you below Y, then you'll survive anyway, and buying a lottery ticket won't significantly harm you. However, if you're already below X, and a lottery win will bring some of you above Y, then buying a lottery ticket still won't significantly harm you (as you're going to die anyway...
I haven't been able to find the source of the idea, but I've recently been reminded of:
This is, of course, based on the Multiple Worlds Interpretation: if the lottery has one-in-a-million odds, then for every million timelines in which you buy a lottery ticket, in one timeline you'll win it. There's a certain amount of friction - it's not a perfect wealth transfer - based on the lottery's odds. But, looked at from this perspective, the question of "should I buy a lottery ticket?" seems like it might be slightly more complicated than "it's a tax on idiots".
But I'm reminded of my current .sig: "Then again, I could be wrong." And even if this is, in fact, a valid viewpoint, it brings up further questions, such as: how can the friction be minimized, and the efficiency of the transfer be maximized? Does deliberately introducing randomness at any point in the process ensure that at least some of your MWI-selves gain a benefit, as opposed to buying a ticket after the numbers have been chosen but before they've been revealed?
How interesting can this idea be made to be?