It's been said before but what Bitcoin really needs to help it become more mainstream is Porn websites, the big tube sites like xhamster & pornhub to accept payments in Bitcoin, Bitcoin is perfect for micropayments and what sites get more traffic than adult websites! There are a few I know LOL but adult sites make up a good percentage of the top 100 most visited sites on the internet.
That may increase its usage, but unfortunately that probably wouldn't do much for its reputation. It's already dismissed by some for being associated with other illicit activities, and while a large number of people do go to those sites, I don't think it would help all that much.
Being predominantly associated with porn websites would be damaging in the long run, this is not what Bitcoin needs.