It often seems to be the concensis that dressing well is only for people who are "in to fashion". I think that is not true. Maybe that's why I enjoy this quote. I like the broader reason it gives for dressing well.
I like it as an inspiration to be respectful of others through thoughtful dressing. While tees and jeans are totally appropriate in many situations, it's important to remember that sometimes they are not.
p.s. Like most things, the quote is best taken in moderation. I give myself a free pass when sick, pregnant, and anytime before 8am.