What would be some benefits of living on a planet with less surface gravity

This is a tricky one.

-- IF I evolved on that planet, then my body is perfectly matched to the
conditions and the environment over there, and I am approximately just
as happy and care-free la de da over there as I really am on Earth,
and I can't imagine living anywhere else.

-- IF I evolved on Earth, and I move this body to a planet with less
surface gravity, then there are all kinds of complications.

. . . Even if the atmosphere over there has the same gases in the
same ratios as Earth's atmosphere, the lower gravity means that the
atmosphere has lower weight.  In turn, that means that the surface
pressure is lower, and I have to work harder to take in enough oxygen to
keep my Earth body functioning.  Breathing alone could be a full-time job.

. . . The acceleration of gravity is less than 9.8 m/s² over there.
This means that when I drop something, it falls slower than I'm used to,
and I can usually grab it before it hits the floor.
When I lift something with the normal force of my Earth arm, it jumps up
faster than I expect.  Until I get used to things, I'll probably overshoot,
lift things too high and too fast, maybe spill the coffee etc.

. . . With my Earth muscles, almost everything takes less force. 
It's a lot easier to walk around.  I bob up and down more than usual,
and my steps are longer.  When I run, it's really funny.  Every time
I take a step, I sail several feet into the air, and come down farther
than I ever did, but it all happens in slow motion.

All of this is fun while it lasts, but it doesn't last long.  My Earth body
gets adjusted to the new planet.  Before long, I actually lose muscle mass
AND bone, so that if I were to go back to Earth, I would be so weak that
I'd have to be carried around for a while.

We know this from what happens to the astronauts who spend 6 months
or a year in zero G on the International Space Station.  Even when they
do resistance exercises for an hour a day, they come back with less
muscle strength and less bone mass.

  concave means having an outline or surface that curves inward like the interior of a circle or sphere. so the mirror curves inward.

If its history of, then b) because a) implies only present day (now)