Would you care to address the contention that even starting with an 18 or a 20 provides what is ultimately a relatively minor advantage in the opening few levels of the game, and that that edge disappears more or less completely after the first four levels or so (due to 5es bounded accuracy)? This is just demonstrabale reality.... and in this converstion so far, No-One who has spoken against rolling has actually adressed it.
I would say that exactly because of bounded accuracy every additional point is very important. The Wizard that rolls 4d6 drop lowest and gets 3 18s can easily have max INT, DEX and CON at level 4. This means 18AC, huge HP boost + way better CON saves, and also best spell attack modifier + save DC for any given level. You also lose the opportunity costs for feats on you next ASI.
Seriously, in a system where the things like the highest AC a monster brings to the table is a 25 every point matters. +1 in my attack modifier is 5% better chance to hit + 1 more damage (usually).
