The first and most honest answer is this: It's about allergies. A lot of people are allergic to metals, myself included. It's actually a funny story, because I didn't really find out about the allergies until I was an adult because I always preferred sterling silver to anything else.
But when I got married to my hubby (almost 14 years -- actually in a few days), I found out I was deeply, uncompromisingly allergic to gold. Oh sure he tried, buying me wedding ring after wedding ring (I go for simplicity, so he didn't shell out a ton of money each time), and each time I had to take it off in less than a weak because my hand would break out.
The last wedding ring he got me, however, is a wonderful design, with a dolphin holding a heart between its tail and nose, that has a wonderfully brilliant diamond in the center of the heart. For not liking diamonds, I sure do love that ring.
Only trouble is: it is 22k solid gold, so I get about two weeks out of it before I start getting a reaction and then I have to take it off and let my hand heal until I can wear it again.
So I chose to only make 14k gold filled and sterling silver jewels -- it makes sense from a hypoallergenic point of view.
The second answer is just a personal preference: I like to feel like the piece I make is going to be an heirloom. Since we already know the pieces are going to last -- knowing that the design is simple and not trendy, but classic and always wearable...knowing that it is made from high end findings really means it will appraise much higher than I sell it for.
I know this because several customers have gotten my pieces appraised, making me wish on a selfish level that I had charged more. But, I don't charge more -- because I want everyone to be able to afford that little piece of luxury I offer.
I suppose it's mostly about bang for your buck -- I wouldn't want to pay too much for something, being the cheapskate I am, so why would I want my customers to?
I wouldn't. I want you have have an item that will last forever, will never go out of style, and that you can hand down to your family members to continue wearing. So, I use those high quality items, and simple, elegant designs.
Plus, as an added bonus, when only working with Silver and Gold, I get to hum one of my favorite U2 songs: Silver and Gold off "Rattle and Hum."
Did I just show my age? Darn...