You sometimes have to remind yourself that the Barclays Center is a sports venue. It’s not just a flashpoint for the Brooklyn gentrification debate, or the place that has overtaken the hallowed Garden to become the most desired music venue in the city for most major touring acts. It’s not just the House that Jay-Z Built (with a wee assist from a Russian oligarch). The reason the arena exists at all is because it’s the home of the Brooklyn Nets. And it’s a fine place to watch a game. Most indoor arenas are bereft of the charm and nuance that make baseball stadiums so unique. But watching basketball at Barclays feels different, cozier, than most of its cousins around the NBA, even that famous one in Manhattan. It has great sight lines (the cheap seats here feel much less so); and the dark color scheme all around the arena (rich browns, cool grays, and, of course, black) makes the shock of golden light that illuminates the smart, herringbone-patterned floor seem almost theatrical. It’s like watching hoops at La Scala…until the droning, monotone “Broook-lyyyn” chant begins. And then there’s the food. All-Brooklyn vendors, an impressive craft beer selection, and probably the best nachos in professional sports, courtesy of Calexico. Next year the Barclays Center becomes the home of the NHL’s New York Islanders, as well. We’ll learn quickly if “Brooklyn on Ice” is as cool as it sounds.