I didn't care much for the first one, so likely wasn't going to see this - but I do agree. Stuff like this is a nice surprise to find out in the movie, though I'm certain there are people that were not going to see this film previously that now will because of this. Hoping for their sake it's not a 3 second little easter egg, haha.
I felt similarly for when Captain America: Civil War advertised Spider-Man.
This one isn't on Gamefreak, the people behind the diamond and pearl remakes made this one.