From my perspective it is totally irrelevant except for purposes of keeping their own distinctions clear. And also because I think it makes Islam appear too alien from Christianity. It has a relationship to Christianity very similar to the relationship Christianity has to Judaism. But there are absolutely groups, all of which were later labeled gnostic, that drew sharp distinctions between God as represented by the Jewish scriptures and the more mystical (Hellenistic I would argue) God that they worshiped.
I do see Islam as being pretty alien from Christianity. Christianity is very different from both Islam and Judaism.