For years, Quince has been a website that I knew as “that place to get affordable cashmere sweaters.” But as its offerings have expanded further and further, from home goods and luggage to jewelry and perfume, it’s also become a source for diamonds , caviar , and even Dom Perignon . The site has been dabbling in gourmet foods and beverages — and I’ve been curious as to why, and whether it’s a good place to buy, say, Champagne and mushroom coffee. If you’re new to Quince, the company first launched out of San Francisco in 2020 as a direct-to-consumer (DTC) lifestyle brand, meaning it cut out the middle man, and thus, was able to slash the prices of typically expensive leather bags , linen tablecloths, bamboo sheets, and silk pillowcases. The initial offerings felt focused: simple, versatile apparel and accessories, catering to the person who might need, say, a silk slip dress for an upcoming wedding. (At Ralph Lauren , one might cost $398.…