The typical lottery is a revenue device: it is intended to get money to the operator of the lottery, rather than any one of the participants. My state's lottery, for example, takes in 40% of revenue as profits, commissions, or operations costs. From a basic search, this does not seem atypical. It's also a sign that this is a very high-friction investment method, even compared to most other random investment methods. Once received, the lottery jackpot is taxed as income or worse-than-income rates, adding further friction.

You'd also need to spend the money relatively well, either to prevent death or so you get significantly more value from the sum than the 'losers' would have from spending the money in other ways. I'm not entirely sure that's the obvious, at least not for most circumstances. ((Worse, rich people tend to have or develop more expensive tastes. If you can't avoid that, the return becomes even more expensive.))

I'm also unsure this is an effective strategy, even taking the rather esoteric assumptions required and the pure utilitarianism. I'd value one person living an addition ten years over fifty or five hundred or fifty million people being slightly inconvenienced, but with sufficiently large numbers the ethics may start going the other way around : you can't discount experiences because someone will end up dead, because it's quite possible all of your MWI selves end up dead eventually.