5e does have a problem with combat taking too long and as a DM i can tell you initiative orders are a major slowdown on combat.
Now, id say the optional rule is... a copout.
Im willing to agree that the way initiative is handled is a departure from DnD.
I think the reasonf or it is simply to make multiplayer more fun and less "wait for the other player to do something and go read a book".
with 4 player coop this stuff takes a while.
