People still dress up at my church - men/boys in coats and ties, and women in suits/dresses/"nice" pants outfits. No hats, but everyone looks so nice. Sometimes my grandsons (ages 7 and 9) fuss about wearing a coat and tie and loafers, but I always tell them it is a sign of respect. I truly believe that - it's why when I go shopping in "nice" stores, I always take extra effort - their merchandise is beautiful and I want to "honor" it by looking my best, too.
Jeans and t-shirts have their place, but one can be casually dressed and look terrific and find something else comfortable to replace them when shopping in Hermes and other lovely stores.
I just plain feel better when I'm dressed nicely! I look forward to dressing up for church each week.