I'm a fan (not a non-fan)--I gather that non-fans often love it, even to where they become more enthusiastic than the ST fan down the line (one of the cruise FB admins is the "non-fan"--his husband was the ST person, but he ended up being more into these cruises). I think it's fun either way--people will be dressed up (including themed costume nights, like Roaring '20s), and there are excellent parties with a good band and awesome DJ. There are fun themed drinks to try. There are shows put on by celebrities every evening, and note that ST actors are usually "other things" as well: Anthony Rapp (RENT), Wilson Cruz (My So-Called Life, RENT), Kate Mulgrew (Orange Is the New Black), Doug Jones (Shape of Water, Pan's Labyrinth, etc.)..and so on. So even if a person's not into ST, they might still see a celebrity they like. I'd also imagine that there are times when normal facilities are more free to use because the ST fans are all doing something.
There's no "normal" stuff, of course. No normal lounge singers/bands, no normal stage show (most of the entertainers are given shore leave during ECP's theme cruises), no normal balloon drop...whatever. And last year, the escape room was closed. However, there are hardly any kids AT ALL. I think we had 2 or 3 under 18s last time, and even in the "before times" (before Covid), it was maybe double that or so? So if the non-fan (or fan) hates having little kids running around and screaming all day, this is a great cruise for it. Of course, you have to put up with a bunch of drunk Trek adults running around and screaming instead. 😄
EDIT, re "Is the pool deck taken every day with huge events or could she swim and enjoy the sun without someone trying to nerve pinch her?"
The pool deck is usually free...there's a launch party on day 1 that she'll want to attend, LOL...celebrities and craziness. There's a t-shirt party on the second day with free drinks for an hour (I think it's held around lunchtime?), and I think the new Collective group party (people with 5+ cruises) was held on the pool deck, although it may have been at an "off" time? I know I felt no need to use the pool then, anyway. But as I say, she may find it a bit more free than usual, too, at other times. I don't know.