Is there any point to sleep more than an hour?

Other than to pass time?

I mean does it increase the time Well Rested/Lover's Embrace will stay active?

I know it doesn't restore more health, as sleeping a single hour appears to restore 100% of lost health, and it doesn't appear to have any other benefit, does it?

Solution 1:

As you say in the question, there is no additional benefit to sleeping more, other than passing additional time.

There's no length increase to buffs, for example Well Rested (which lasts 12 hours from awakening regardless of time-slept).

Solution 2:

It is used for role-playing.

If your character has the "Night Person" perk, then he will mostly be a night person, so he will be sleeping by day (or the other way around if having the "Solar Powered" perk.)