For what, immersion? Or is there some kind of benefit from doing this.
They are doing what the USAF is doing. USAF Red force used to live, eat, speak, think and fight like the Soviet/ Russian pilots. IMO, they will have if not already have, aided by Taiwanese, a Chinese speaking, think in Chinese and fight like Chinese pilots using PLAAF tactics in the USAF Red force.
It makes the simulated fights between Red and Blue more real than other wise. One air force, 2 different fighting tactics and styles, and speak different languages in Red vs blue training.
UASF Aggresor/Red Flat Red vs Blue training is the result of air battles in Vietnam war. It has been proven to be very useful in building up pilots' experience against an unfamiliar enemy aircraft and tactics, and cut down losses in real air battles.