>>83265701You have to invest money to make money. Mint has a huge pull, so her being a special guest leads to increased interest, higher ticket sales and better brand recognition. It's very easy marketing concepts and the fact that /vt/ doesn't get it speaks volumes about either their education or their mental capacity.
The ulterior motive would be beneficial for Lia in the 1st place, not Mint. Mint is her oshi and Fishman makes this dream come true even sweeter. Everything else - and by that I actually mean everything: the hotel and flight, the 3D, a literal sandwich - is either some business expense, business travel expense in particular or just common courtesy.