Judging by the plot, Itachi was preparing to give Shisui's Mangekyo to Naruto, setting a trap for the future Demon Sasuke.
Liao Wu wanted to obtain Shisui's Mangekyo and master Kotoamatsukami.
He had to get his hands on a Dojutsu with such absolute control. If he encountered someone he could not control otherwise, he could use Kotoamatsukami on them.
Deidara, for instance, refused to behave. Right now, only a Sealing Technique kept his chakra sealed.
If that seal were released, Deidara might blow himself up on the spot.
So once Liao Wu obtained Kotoamatsukami, he intended to use it to control Deidara.
He could also wait until his Wood Clone summoned his past original body from Rōran. Once his original body arrived in this world, he could use Yachihoko to control Deidara.
Itachi stepped out and called toward the dense woods nearby, "Naruto Uzumaki, come out!"
Itachi had clearly come looking for Liao Wu.
Liao Wu emerged, reining in his wandering thoughts and perfectly acting out Itachi's impression of Naruto.
"Uchiha Itachi, are you here to capture me?"
Itachi shook his head. "No, I only came to talk to you about something!"
Liao Wu's Shadow Clone drew a kunai and charged at Itachi, a move that perfectly matched Naruto's recklessness.
Once he decided someone was an enemy, he would grab a kunai and attack!
Itachi easily destroyed Liao Wu's Shadow Clone and said to him, "Why are you so fixated on my little brother? He's a rogue ninja now, isn't he?"
Liao Wu said, "Unlike you, at least... I'll treat him like a brother!"
"..."
Itachi fell silent.
He thought of himself. Sasuke was better off than he was. At least Sasuke still had a fool like this who would never abandon him and would choose to believe in him.