Sunnies feel good, help you avoid your phone before you sleep, and are a great excuse to relax and let your mind wander. But, they also have a few tangible benefits:
Wearing them before bed can help you fall asleep. Here's a scientific study that shows periocular (around the eyes) heating can help people fall asleep faster.
For patients with dry eyes, doctors often recommend warm compresses before sleep. Sunnies can offer similar benefits without requiring setup or cleanup. If you have issues with dry eyes, check with your doctor if sunnies could be a suitable remedy.
Heated eye masks have been shown to improve vision in people who use screens throughout the day. No, they're not going suddenly make you see in 20/20, but they can increase accommodation (time to focus) and acuity (sharpness) after use. Read about it here.
This one is a bit obvious, but avoiding blue light before sleep is proven to help you fall asleep. With sunnies as part of your nighttime routine, you'll be spending less time on your phone before bed and therefore should sleep better.