I don't think it either hurt, nor helped to be quite honest with you! It advanced the angles at the time, but really after it came and went it was merely an afterthought, and I just didn't care once "Unforgiven" rolled around. The feedback to it was positive, due to WWE's "Attitude Era" prowess, of Crash TV. It was momentary, and it worked!
When Mac won the belt the WWF was red hot, and to the casual viewer or fan, who attended the show, or were watching on TV, it was legit shock, and the crowd reaction afterwards, was positive, I also think in the eyes of many WWF could do no wrong! Someone earlier said, this was before the Arquette and Russo reigns! Maybe that's why it's not as balked at, or as talked about as those two, because it was different, fresh. And in all fairness, Vinny Mac, had actually headlined a few PPV's as a wrestler, and had drawn very well, so there ya go.
That said HOWEVER, in my opinion it was definitely pure egotism, and I love how a guy who just two years before ranted about "Time Honoured Traditions", broke one by not dropping the belt himself, and he had no real excuses, he wasn't on his way out. But it came and went within the span of not even a week. And they didn't milk as much as they very well could've.
As for Arquette, he's an actor, who's only experience with wrestling is being in a movie about one. And not a very good movie at that. Vinny Mac had at least drawn a penny in wrestling in terms of his character, in '99, Arquette barely drew a penny in the Movie Box Office. And remember what I said earlier, about WWF doing no wrong in the eyes of some in late '99. Well, by mid 2000, WCW could do no right, and this just made things worse. Same with Vinny Ru's win later in the year.
To me it was all about the atmosphere in each respective company. That said however, it makes a lot more sense to put the belt on the 54 year old owner of the company, who has a "little bit" of wrestling experience under his belt, has actually headlined a few PPV's and drawn well doing it, and has at least half an ounce of credibility. Over an actor or a writer, who had none of those attributes.
That's my take...