I think the numbers for the draft are always exaggerated. They claimed almost 800,000 over 3 days in Detroit. They are nothing but estimates…similar to how numbers are always blown up for parades and outdoor festivals.
That being said, if Green Bay can host it, so can Buffalo. A large majority of the people are locals who have no need for a hotel room. For everyone else, plenty of room between Buffalo, Rochester, Erie…and even Southern Ontario if the demand is that great.