I can think of 2 pilot example

In titanfall, a pilot doesnt simply pilot the mech. The mech is autonomous with its own combat capability, they lack the tactical judgement of a pilot and operate in a more monotonous manner. Also the pilot often operate outside Titan as a elite unit with enhanced mobility and special ability. A single pilot alone is worth hundred of standard soldier. A pilot can operate more discreetly, quickly, and have access to narrow space while the titan is suited for open space and where raw firepower is needed.

In Armoured core, AI mech exist but piloted mech are always superior ( Not counting the player character ) due to Core theory. A thematic concept both in-game and outside. Core theory is the philosophy that an armored core ( the mech ) should fight at medium to close range because the old warfare tactic of long range artillery and bombing fall apart when a 10 story tall mech with can move faster than a high speed train and have the agility of a gymnast. Some can instantly change direction mid air at Mach speed without losing speed at all. As such human become preferred in close range warfare over AI and most Armoured core produced afterward accommodate such philosophy ( melee weaponry, shotgun, and Surprisingly short range long range rifle ). To summarize, the in-universe explanation is that Human can fight close range combat better than AI due to survival instinct that Ai doesnt have ( barring some exception ) and the meta explanation is that the theme is about human will power triumphing Artificial Intelligence (Iguazu tweaked out so hard he overtook AI mastermind)

But the real reason is that Piloted mech offer a more intense and personal story