Agree with mattie too. I love big organised displays, but also having animals who are terrified think that the ones that people have in their gardens are just pointless really. One family pretty close to us have some every year....about 4 or 5 to be precise, with about 10 mintues in between while they faff around trying to get the thing ready to light. I only think they look impressive if they're part of a proper display.
I know of people who have been badly injured by fireworks, so personally I think it's more of safety issue why they should only be sold to organisers of public displays - the results can be horrific if they don't get into the wrong hands.