(ok I was ninjaed several times already, whatever...)
amok: to bad they never have any iOS bundles.
I'd guess that has everything to do with Apple locking the devices down so that people can't install iOS apps from outside Apple's store. Unless they jailbreak the device. I see no other reason why they wouldn't want to sell the games also to iOS.
The HiB Android games are downloaded or transferred to the device irrespective of the GooglePlay store, and they don't need any activation either with any certain account. So they obviously are fully DRM-free, which is why I prefer getting my Android games from HiB instead of GooglePlay (whose DRM is still a bit of mystery to me).
However, it appears to me that at least some of the HiB Android games are recognized as "installed" by GooglePlay, when you browse the same games from GooglePlay catalog. I don't know if that means you'll receive updates through GooglePlay for them, even though you didn't buy them through there.