This is a Morbidelli aluminum monoquoque road racing motorcycle. The paint work is decorative, but every other aspect of all this work was driven by utility. The curves in the bodywork are a compromise between the need for the rider’s ability to move, the mechanic’s access for repair, the aerodynamics of traveling at high speed and the need to provide sufficient airflow for adequate engine heat dissipation. Even the graceful radius of the curves resists the vibration fractures that sharp angles tend to encourage.
Don’t look at all that, though. Don’t get bogged down in why a hundred decisions were made decades ago. Just look at what it is now.