Pre-Flashpoint Booster Gold had a rough life since his best friend died and he became a Time Master. One of the things that made his burden a little more bearable was having a hero like Batman know the truth. But as is the case with many superheroes Bruce Wayne was assumed dead and it left Booster in an awkward situation with the new Batman Dick Grayson. After going on a mission to save Dick and all the other Titans from dying in the past the truth comes out. Dick asks for a "reminder" and Booster takes him on a trip to show what's worth fighting for.
It's really a small section of the arc right at the end but it says a lot about both characters. It's very telling how Dick differs from Bruce. While Dick does interact with Booster after this in JLGL nothing really comes of this connection. It's unclear why New 52/DCYOU Bruce Wayne was Boosters' biggest supporter. Or if that's been retconne like most of Jurgens JLI. Still this BG tale is a nice small moment of joy in both heroes lives. Bruce gave Booster the support he needed and Booster returns the favor with Dick.