Not just face reasons. Remember what happened with that Boeing 747 they bought for the Chinese leadership to use. It turned out to have been ridden with bugs and other listening devices when it they added the interiors for it in the USA. As a result the Chinese leadership today uses a bog standard Air China aircraft requisitioned on a case by case basis instead of dedicated one.
First it was a Boeing 767.
Second the Chinese never produced the bugs. Which is questionable as hell because during the conversion it was under PLA supervision, and as Comrade Khrushchev proved the best way to egg the west’s face is to show the device with the information plate that reads “Made in the USA”. Since the reports of the bugging some other reports emerged that shifted them from NSA to CCP. Infighting and factions inside the CCP are not unheard of.
Third, No the Air China 747 are known and they don’t randomly pick one they have a set number in fleet 10, and one configured on specialized aircraft with modified interior. Though used commercially that aircraft’s much more flying office than standard first class/Buisness class, Coach. The two aircraft were a B747-400 tail number B-2472 and a newer B747-8i tail number B-2479.