It's not the worst song in the world, but...1. It's considered to be a camp song: a fluke that hit the top of the charts and then took a rebound and hard left into the gay community, where it settled in for a permanent stay. That's given it a bad branding in a lot of voting fingers. (As noted above, her picking this one could gain votes, but there's a very real question of where the total finishes up on the plus/minus.)
2. First impressions... she's establishing the majority of her contestant character on Song #1, especially since we saw pretty much nothing of her during the audition stage. (Thanks, editors!) For better or for worse, a lot of people are going to fix on her as the Weathergirl. Whether she gets a chance at a second impression...
3. It's not really a solo piece. It can be performed as one, but you'll probably lose something: this one's designed for a group effort. You don't get a lot of note range across the verses either, so if she wants to show off, it's the wrong song to do so with.
4. Is she actually going to try and reinterpret it? What exactly could anyone do with the thing? Ballad? Slow mourning chant? Factual weather report?
I'm not confident.