Waiting in line is still better than showing up super early and not getting in a boarding group (or having to wait around all day for boarding group to be called). I can imagine getting there super early - with your young, cranky family. Getting a BG, but it not being called until late at night (past the normal time you would stay in the park with your young family). Not family friendly at all.
To me, BGs are millenial friendly .. childless, 20-30 something vloggers and local AP holders who have no issues driving to the park and getting there early. Who are not beholden to a vacation plan they planned out months before. They are able to show up whenever multiple days and just try again if they fail the first time.
It doesn't seem very friendly to guests who are there on a 4-5 day vacation and can really only go to DHS one day and can only move as fast as their slowest member.
I mean BGs seem like a horrible hybrid of the FP+ system and the old paper FP system.
You are forced to get there early (like the old paper system) but have no standby option if you dont get a ticket.