One reason people might get in a standby line even though FP return time is not far out is that they are already holding a FP for something else and aren't eligible to get another one.
True. And this is why I am really thinking that I will move most of my FP+s up. I don't care how much time I "save," I only care how much time I spend.
Those individuals in line at PotC at 2:15 when SB is 30 minutes (all made up) can't get another FP+, even though one is available right now, because they have FP+s for BTMRR at 3:00. So, they spend 30 minutes at PotC so they can save 60 minutes at BTMRR. I'd prefer to skip both of those SB lines entirely.
Now, I do RD once per trip (if even). We are normally in the parks within an hour of open. I actually dislike waiting in line to get into a park to wait in more lines, so even if I am awake, I'm not at RD.
So, my goal is to ride these rides in one day with minimal wait: Space, Splash, BTMRR, PP, WtP, Barnstormer, Buzz, Speedway, PotC, JC, and maybe HM. I'm sure there are others we'll throw in.
If I use Space, BTMRR, and PP at 9:00, 10:00, and 11:00, I might be able go get Buzz for 11:15. Then, as soon as I ride that, I'm onto the next one. I'll likely save Splash for later in the day or, if it happens to pop up with an early return time, I'll grab it. So I am minimizing my time spent in line if I'm not waiting in any SB lines (other than for the carousel and People Mover and such). Even if I only "saved" 25 minutes when I could have saved 90, I was never going to wait in a 90 minute line, so that's not super-relevant to me. I would have moved on to another lower-wait attraction or come back to ride at park close.
I think both are good and valid strategies. It will be interesting to see how the extra FPs work when it's busier. I'll be there in 30 days, and much like Shaden, I'll be testing the heck out of this.
I'm already thinking about cancelling all my FPs in EPCOT in advance other than Soarin' to see if it will treat me as having no valid FPs and eligible for another Tier 1 and/or hopping, or if you actually have to use three per day before you can grab another. Very interested to try it all out.