As far as I understand, Blukstack's team was rank 2 at 00:00 on the 28th, so that could be one reason why they were invited. Another reason could be that Blizzard saw that they had been rank 2 for a while and just got overtaken in the middle of the night soon before server shutdown, so they thought they deserved the invite anyway. I might be mistaken though, this is just what I remember from the other discussion about this.
it's disgusting that there is no player riot because of the eu invitations
I do however agree that watching 2-3 LSDs and a bunch of other wizard teams play against each other is probably going to be very boring.