It's true that technically, it's only Codex: Space Marines at the moment. That being said, Games Workshop wants you to buy models. In their own stores, they've been known to encourage non-Blood Angels or Grey Knights Space Marine players to pick up Stormravens and use them in their games, because... well, why not? It's a Space Marine vehicle, and it's pretty clear that all Chapters have them at this point.
I picked up a Stormtalon, and I use Codex: Blood Angels for my Lions Rampant Chapter (who are Ultramarines, genetically, but Assault Squads being Troops lets me play an army with a heavier emphasis on Fast Attack, which is much more my style.) Nobody locally has any issue with me using it as it appears in the White Dwarf-- especially since frankly, the Blood Angels have much more effective, durable, and competitive options which do similar things. Honestly, I look at the thing as GW's compromise with their internal agreement with Forge World-- they wouldn't directly port any more Forge World models like they did with Codex: Tau, and that meant they couldn't put the Land Speeder Tempest out as a kit, even though that's really the Space Marine air superiority craft. So they came up with something new instead. I mean, the thing is even armed in a remarkably similar way to the Tempest, is comparably durable, and costs a similar amount. And anybody can take a Land Speeder Tempest.
The one place I don't know how well a Stormtalon would fit would be Codex: Space Wolves. Kind of for the same reason the Wolves don't care for jump packs much-- Leman Russ taught them that a warrior's place was with both feet on the ground, and not flying around in the air.
IN THE US? ASK ME HOW TO GET 10% OFF GAMES WORKSHOP PRODUCTS!