But when looking at a possible positive outcome, such as the lottery case, it can "make sense" to buy one ticket.

Your chance of winning goes from No Chance to A Chance, which is an infinite improvement.

That's not how this works as a rational investment choice.

It's true that you can never win a lottery you don't enter, but the expected value of that ticket is vastly lower than what you paid for it. That means, as an investment, your $10 will be expected to do better in literally anything with a positive return.

If you are buying > $10 worth of dreaming (for you), fine - but that's consumption.