I bought Shadowbeat when it came out in 1992. That was probably the first time I read a gaming sourcebook with the awareness that I would probably never use any of its contents, and not minding in the slightest. I read it cover to cover in one sitting for the sheer joy of it.
I was wrong, actually. Later I ran a campaign arc featuring Urban Brawl, and then another one about the music industry, and Shadowbeat turned out to be very useful ... but I didn't know that when I bought it, and it wouldn't have mattered to me if I never found a use for it. It was just that fun to read.
Some Shadowrun books are like that, and that's why I love them. The Attitude sourcebook in SR4 and now No Future in SR5 revisit the same ground that Shadowbeat first mapped out back in SR1, and it's still a blast. I don't buy the books because I expect them to contribute immediately to my campaign. I buy them because I love the glimpses they provide into everyday life in the Shadowrun world.
Indirectly, I think they help me paint a more complete and compelling picture of life in the Sixth World. The latest Urban Brawl match on the big trideo screen at Reno's during the meet with Mr. Johnson ("Screamers are leading the Paladins by two points in the third quarter"). The security guards chatting about the latest episode of Chase: Errant Knight while the runners sneak past ("Could you believe it when Muñoz got shot in the eye?" "Dude, spoilers?!"). Searching for a target in the crowd at a Fragging Unicorns concert ("sorry, guys, but Rev. Blackfeather is really killing it tonight, and the audience is kicking up a higher astral background count than expected").
Maybe later some of this content will inspire a truly epic shadowrun, or story arc. Maybe not. Don't care. I eat it up either way.