It's not a weird wish at all!! you'd be surprised how many people did stock trading nowadays. In their case it actually lead to him being able to buy the apartment ;~;
It's so beautifully rounded, though, that what he wished for made it possible for Daiki to buy teh apartment that will be their home together. He wished for something that ended up being his own happiness. :D
^THIS! Exactly the point why it ended that way. He made that wish for Daiki because that time he really didn't have anything to wish for (or so he thought). Little did he know that THAT wish will make a significant change in his life.
What a weird wish...
Well, I'd probably wish something cliche , like have good luck or something like that
╮(￣▽￣)╭