Regarding it increasing his chances of winning, it's not unreasonable to theorize that some relatively apolitical voters (it is a special election, after all) may not have been particularly excited by Moore before, but now that they see the "fake news media" and establishment furiously attacking him from both sides, they will actually turn out to vote for him.
That's a good point. This could catch the attention of more voters who weren't paying attention before and that might not be a good thing for Jones. On the other hand, it will also catch the attention of AL democrats, who given their long history of demoralizing losses, may need special motivation to turn out in non-presidential races. I think Jones was always going to have trouble getting the kind of turnout he needed among Dems, so from that point of view, this could at least help him with his own gotv ops - especially if the dems start to believe they might actually have a chance of winning for the first time in who knows how long.