There are some nice camp sites there, constructed by trail crew people who built the original trails, I believe. I've seen people camp there, and it is certainly a valid option.
Here's a satellite
view of the sites -- I can spot about 8.
You've got better eyes than me, I'm having a hard time picking them out

Are they below the JMT/Whitney Trail Junction?
Seems like it may be a good backup plan if we start the climb from Guitar Lake and decide we don't want it go all the way to the summit. It would give us nice jump to make the summit by sunrise, while allowing us to leave our heavy packs at the junction.