I like rolling more for the element of chaos than any pretense of "realism". Clattering dice on the table and then figuring out how it makes my concept easier or harder is fun.
That said, I always allow players to use the standard Array if they think their rolls look unfun.
And really, that is the most valid reason for using one or the other - one way seems more fun to you.
Neither is inherently superior to the other, except on a personal preference level.
Some people like the uncertainty of rolling, others prefer the control of point buy/array. Ultimately it's the DM's choice for their game, but it is usually heavily influenced by the player's preferences (if they have one).