I was just going to say that some of the biggest competitive games played these days spawned off of mods.
There is not a single thing wrong with making a competitive community around a game mod. People play whatever they like... mod or not.
There is nothing wrong with the Smash community playing Project M competitively. It's really on the game developers (ie. Nintendo) to do something about it. Put out a better god damn product than Project M, ignore it completely or order a C&D against it. Gamers will do what they gotta do.
Item economy introduced in August 2013 had a significant impact on the game's popularity. Valve even cited this as a reason.
So literally what Infaanator said... they put Hats in CS and it went big.