This is a personal decision (and controversial in the tattoo world) I would say.
I do this. I don't have it covered during day, at night I wash it and apply ointment, I wrap it up but very loosely, sometimes it's rolled down (or up) when I wake in the morning tho but doing this method (for 3 nights) I have never needed a touch up, I have 8 tattoos, including both calf's completely covered. I never would recommend wrapping it tightly tho.
As my artist suggests it's a great way to keep the tattoo moist, it stops you ruining your clothes/sheets and stops the tattoo.from sticking to the sheets.
But there is a rule - follow your artists advice. If they are covered in tattoos and most are, they themselves will do the same, they would never tell you something they don't do.