Yes, it was true, Alfin has chosen to expose the great collapse of dimensional passageways to the whole world.
His reason for doing it is nothing more than just a desire to enjoy some chaos and this would also give Wilkis something worse to think about while Alfin's people go on and complete the mission.
Which would make it the perfect diversion, masking the small negotiation that would happen soon after his employed players arrive in Thorn city.
Otherwise who knows, what kind of other eyes someone as paranoid as Wilkis has placed in Thorn city? And knowing him, he probably would have a bunch that would follow all the players after they enter the city.
Something that Alfin doesn't want to happen. He wishes to keep WIlkis in the dark.
'Hah, I still wonder whether he will curse me for exposing this information to the whole world.'
And of course, he just might.