For some perspective, CD trays, like the PS2 and Xbox had, that retracted mechanically were viewed as sleek and futuristic, and that's why slot loaders like the Wii and PS3 gained traction too.
It was an aesthetic choice, like the move from green LEDs to blue, though that has historic significant as blue LEDs are a relatively recent invention as the were incredibly difficult to figure out, so blue LEDs were seen as futuristic and opulent and used in everything consumer electronics for a while.