The chrome lined barrels were designed for heavy rate, sustained, autofire.
In a standard AR, you don't need a chrome lined barrel, though they will last a little longer, they are just not as accurate.
For a minute of bad guy weapon, chrome lined barrels are fine.
For a varmint shooter at 500 or 600 yards, then you want more of a dedicated accuracy barrel.
Chrome lined barrels are more forgiving and easier to clean, but the 5.56/.223 round is particularly fast, nor is it a high pressure, "barrel eating" type of round.
With good cleaning and moderate understanding of firearm's maintenence, a normal barrel will last you much longer than you will probably use the weapon, to be perfect honest, in most shooting situations.
Now, if you are part of a tac-team, with entry drills, live fire scenarios, thousands of rounds a month leaving the weapon, yes, you would prefer a chrome lined barrel.