No matter how you feel about interleague play, it's hard to find much fault with the yearly home-and-home series between the Giants and A's.
Fans from both sides pack the ballparks, particularly in Oakland. For years, when Oracle Park sold out every night, that was the best chance that Giants fans in the East Bay had of seeing their team up close, and it remains a much closer trip. There's a lot more media for those games, and I can say from personal experience that I've always loved having the opportunity to watch someone like Matt Chapman in person for three days.