I believe that my death has negative utility. (Not just because my family and friends will be upset; also because society has wasted a lot of resources on me and I am at the point of being able to pay them back, I anticipate being able to use my life to generate lots of resources for good causes, etc.)
Therefore, I believe that the outcome (I win the lottery ticket in one world; I die in all other worlds) is worse than the outcome (I win the lottery in one world; I live in all other worlds) which is itself worse than (I don't waste money on a lottery ticket in any world).
Least Convenient Possible World, I assume, would be believing that my life has negative utility unless I won the lottery, in which case, sure, I'd try quantum suicide.
thus creating an outcome pump for the subset of the branches where you survive (the only one that matters).
What? No! All of the worlds matter just as much, assuming your utility function is over outcomes, not experiences..
The LCPW is the one where your argument fails while mine works: suppose only the worlds where you live matter to you, so you happily suicide if you lose. So any egoist believing the MWI should use quantum immortality early and often if he/she is rational.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.