It started as a aero, and weight item long ago. Smaller , and better options for in the tucked position. However many of your 250,300,500 CC kids cant afford a good micro mirror. I've been using bar end mirrors for 20 plus years. CRG , and a friend makes custom mirrors for my hyper bikes. There are mirrors on the Hayabusa .
Images from this website were taken from my Hayabusa , and Tiger1200XCX. The DL1000 was down in Big Bend Tx. Another image with key in the side case was on the Hayabusa.
Often removing stock mirrors cleans up rider felt air on sport bikes.