It's not obvious to me that the boarding process they're facilitating is even necessary in the first place - what purpose does lining up serve? I've never seen anything like it abroad, including at far busier stations than 30th Street, and SEPTA doesn't seem to have found it to be necessary at 30th street either. I'm also not aware of its ever having been used back in the Pennsylvania Railroad days, although that was well before my time.
To this naive observer it just looks like an unnecessary hassle at best, even when the people running it are in a good mood.
The contrast between Amtrak against NJT and LIRR in NYPS is so obvious. Amtrak's Kindergarten lines to the one stairway down in the legacy Penn concourse, (though have stopped looking at people's tickets) and now another in Moynihan Concourse (which of course deliberately lacks any nearby seating - like lining us up in the school yard, hence the term), but commuter rail passengers can load 1,000 people through all available stairways to a particular track from any concourse (Moynihan, NJT 7th Ave, LIRR , upper level Penn main, lower level central, west) once they see the track number.