IMO, the majority of players traveling to tournaments should NOT be traveling with the "expectation" of winning said tournaments. They should be traveling to tournaments with the intentions of supporting the game, enjoying the tournament experience with the game, enjoying time spent in the company of fellow supporters of the game, and utilizing the time there to make themselves a better player. Leave the "playing to win" mindset to the top players, sponsored players, and/or those few LEGITIMATELY seeking to be the best in the world.
With that said, if you are a player, and are not top, sponsored, or seeking to be best in the world, and you WANT to play a low-tier character (Helena, Lisa, Zack, etc.), then you entirely SHOULD play that character! Take inspiration from a guy like Awesmic who NEVER DROPS CHRISTIE. And who knows ... you just might discover something with the character no one even knew was there, or might become a low-tier hero by performing beyond expectation at a big tournament (ala GamerBee, HumanBomb, Mame Spider, etc).