Us, we don't need the CM to walk us through the packet of info.
FWIW, they always walk us through it anyway.
We do split stays, so our trips involve a few checkins. The ONE time I didn't do it online was the one time we got a cruddy, only thing available, room.
And at some of our picking-up-the-packet experiences when we've done online, the CM hasn't liked the room we were assigned and changed it anyway. It has never been a "here's your packet now go" experience for us, even when we've wanted it to be.
As for saving time in line...when we went to pick up packets at OKW we stood where the sign told us to, which was in the concierge desk line. And the people in front of us took awhile (and that's totally fine!) so I didn't see much time-savings. Another time at OKW we were arriving just as a HUGE number of people were doing checking-out processes before boarding a cruise bus (I *think* it was during a
DVC cruise), and the room was just packed. That time, as I stood where the sign told me to, a manager came out and got the process started, then told us to go to a certain "window" (which was in the normal checkin area).
At BWV there was one person at the normal window and no one at the online checkin window, so very little time was saved.
Anyway, so far, the one time we didn't do it we didn't like the room. Each other time, though, has worked out well.