canaaniteshift - You asked why this inscription is considered to be so important. Well, it supposedly justifies a hijazid locality for the origins of Islam. That is one thing. Another thing is that is attests the historicity of the second caliph Umar, since the date on the inscription is the same year Umar is said to have died. .
OK for the synching of the historical figure of Omar, who is mentioned in outside sources, and the Islamic narrative regarding him, at least with the date. The hijazi locality doesn't seem to be as significant because by this time the Arabs had even reached Egypt. Although if it supports the narrative, then that gives further credence to the story as whole I suppose. What does this group think of the Othman inscription by Qays the scribe?
Altara, nobody is trying to undermine Christian influence on early Islam by stating the Arabic script comes from the Nabataean, and I suppose it is important write it in full with you, the Nabataean Aramaic script. In fact, all early Arabic inscriptions are Christian - Jallad makes this point very clear. He states that the epigraphic evidence proves that Arabic script and language were considered appropriate ways of expressing Christian identity in pre-Islamic times and goes on that from the epigraphic record there is no evidence for paganism in the 6th century. It does not seem to be an effort to deny ARamaic or Christianity but to identify WHICH Aramaic and WHICH christianity.