I had a twitch of excitement over this

I've certainly admitted that I am a soccer fan, and am a little disappointed that there isn't an MLS franchise here in the Twin Cities. Granted, the Major League Soccer experience is significantly less than that of their counterparts overseas. The talent level is lower in the States, the international competition is non-existent and the entire nation doesn't get involved because there is no relegation, and no opportunity for smaller markets to get involved (never mind that soccer just isn't that popular in America, though it is getting there).
Still, the announcement that the new Vikings stadium in Minneapolis may lead to an MLS franchise here in the Twin Cities is one of the better side effects of the deal. Consider the positives for the region. There is no cost to the state or city for the team, as they would play at the new Vikings stadium. It would add another crowd to Minneapolis, and perhaps an additional source of tourism.
Yes, when talking about the positive impact of tourism a new stadium provides, any football based argument is BS. There is no value added, because it would not attract any new tourists. There would be a one time bump after the city gets the Super Bowl one time, but after that? Nothing. Soccer, on the other hand, actually has a chance to provide a bump to tourism. Nothing significant enough to build a new stadium over, mind you, but again, there wouldn't be anything invested in a soccer team by the state, as this stadium is being built with or without them.
With an MLS team, there would be exhibition matches, typically with foreign opponents. While Americans likely have their own opinions of the Twin Cities and Minnesota that a new stadium wouldn't change, there are a lot of Europeans that have never heard of Minneapolis. This is where a positive first impression could be made. Consider the inverse. Residents of England know Manchester to be a dirty industrial town, not much worth visiting. Soccer fans know it as a destination, thanks to their strong soccer clubs of United and City. Getting random foreign eyes on the Twin Cities would help raise the international profile of the city. Finally, a catch-free benefit to the new stadium.