Would be easier than bugging the embassy and having it detected.
And could explain why Saudi Security partied like it was 999 on Khashoggi if he was personally bugged.
Khashoggi was arguably the leader of the Muslim Brotherhood in Saudi Arabia - at least he was the most recognized face of the movement there.
President Erdogan is the biggest State sponsor of the Muslim Brotherhood in the World today. The leadership of the Brotherhood now live in Turkey as guests of the Government, after the military coup drove them from Egypt.
I believe that is the main reason Khashoggi went to the Saudi Consulate in Istanbul - he knew he needed strong protection, after having publicly taken a stand opposing the Saudi King and Government for the last year, and setting up an organization (DAWN - Democracy in the Arab World Now) dedicated to overthrowing the Saudi Government. He had taken treasonous actions far in excess of what is needed for a death sentence in the Kingdom.
I doubt that Khashoggi would have dared to set foot into a Saudi Embassy without assurances of protection from Turkish Intelligence. The Saudis are well known for Rendition (kidnapping) of Saudis around the world, to face Saudi justice back home. He may very well have been there on behalf of Turkish Intelligence, as a rep of the Brotherhood, with the whole divorce thing just being a cover story.
Jamal’s billionaire uncle Adnan Khashoggi was a long time Intel operative, who played a big role in the Iran Contra Affair in the 1980’s. Jamal was raised inside spy society, and has been taking a role in it his whole adult life.