[Can anyone give a credible explanation of why aliens would want to visit earth?]
It’s the same as people from the city driving out to Amish country on the weekend.
Farmerbob wrote: “It’s the same as people from the city driving out to Amish country on the weekend.”
Only if the Aliens have mastered faster than light drives. Otherwise, that ‘day trip’ to visit the Amish takes a few thousand years.