Okay, I had plans to fly from:
ONT (Ontario, CA) to SJC (San Jose, CA)
then later, SJC to GEG (Spokane, WA), stop in Phoenix, AZ (PHX).
Then, home from GEG to ONT.

So...
Checked in 24 hours ahead out of Ontario.
Paid for Business Select from San Jose to Spokane. Checked in 24 hours ahead.
Checked in 24 hours ahead from Spokane to Ontario, with plane change.

Bottom line... On EACH flight, I could've sat RIGHT UP FRONT. I got a few extra points and a free drink by paying for Business Select from San Jose to Spokane. Also, any monkey with a crutch under or a sling over his/her arm can procure the magical "pre-boarding" positions, and sit wherever the crap they want.

So, as far as I can see, the only reason to pay for "Business Select" is to get the extra points.