While the leak was illegal, in the case of elections, personally I am all for anything that brings voters a better understanding of the candidates. Misinformation is untrue, and people can generally see right through it; email leaks are true. Given the polarization at the time, I don’t think that the email leaks had an impact on the outcome, but voters did become more informed, and that likely swayed some votes. Educated voters are a good thing in my opinion.