I understand that USB modems are often seen as a drive mount-point, due to them frequently having an additional port to plug a microSD card or similar in. I used them myself in the past, so I know all about that.
But I can honestly say this is the first time I've ever seen one show up as "sr0"; the primary optical drive mount-point...!! (Mind you, seeing it's a Huawei, I wouldn't put anything past 'em...)
Mike.