Their "dress" line (Cellini) is all quartz, too.
Yes, technically, your average Rolex is not considered a dressy watch, but rather a "Sport" watch. Dressy watches, almost by definition, must be on a strap, not a bracelet (That said, my inherited 50s steel Datejust, which is a little retro-looking, makes a darn good accompaniment to a suit).
The funny thing is how most people seem to think Rolex is a) a fancy watch, and b) top-end. They're neither. They're reliable (by mechanical standards), but relatively mass-production, with a focus on function over fancy features. They can come in expensive/gaudy cases, but they're pretty simple in the world of "nice" watches. That, and a ~$5k Rolex looks cheap next to the 20-50k Patek Phillipe a Wall St. CEO might likely wear to work. To say nothing of the "boutique" models....