From my experience in the US and Canada, people that are actual soccer fans already have a club they support (typically one of the 'big 6').
Then you have the people who like soccer and follow it more causally, and again they typically 'support' one of the 'big 6' or even a few clubs from...
It will probably be hard to assign any tangible benefit, at least for a few years. But as others have said, increases the clubs profile and could attract new sponsors.
Do we know who's keeping the ticket sales?