Brisk walking [every day even] doesn't qualify as a moderately active lifestyle, sorry.

If it doesn't raise your heart rate to at least 100+, it's nearly useless as an exercise. Sure, you'll burn slightly more calories than sitting at a desk, but the benefits are nowhere near actual exercise.

> more and better quality sleep, better friendships, etc.

Sleep quality generally improves with exercise, as long as you're still getting 8 hours. Better friendships are completely orthogonal to exercise/weightlifting.