Any question answered...

At best, the hope that you might win, the feeling of taking part in something positive (all that money for charity), the excitement of waiting for the draw, all can be worth paying for even if you never win. It's not that different from spectator sport.

At worst, it is cynical exploitation of people who have so little hope in their lives that the above transaction makes sense to them.

Since we're being serious all of a sudden, it's not a tax it's optional. Aside from your points, lottery funding has done a lot of good, not least to the British film industry.