Oh it's absolutely a joke. Imagine a person putting a case protector on a Rolex. Or a Patek Philippe. It's expensive, so why not right? No. Just no. And I'll explain why.
1. A large part of what you're purchasing is the design. As much as it pains me to admit it, because you're wearing it, and it's on display always, it's somewhat anyway, a part of your fashion. So when you put a case on it, you're saying you've got better ideas than it's designer, about how it should look. Trust me, you don't. And if you do, save yourself a boatload of money, and buy a G-shock. You'll still be able to tell time, and you'll have the bulky load of plastic look on your wrist that you're going for.
2. The Apple watch isn't THAT expensive. I mean, the Edition is, sure, but if you buy the Edition, who's only differentiating factor is it's build in Gold, and then you put a case on that, you're the biggest idiot of all. Might as well have gone with a sport and put the same case on it.
3. This is going to come as a shock, I know, but the Apple Watch isn't the first stainless steel or gold watch to exist. There's been at least a few before it. Oh, and I think a couple of those may have had sapphire crystal too. Me personally, I've owned 4 stainless steel watches with sapphire crystal in the last 10 years, and you know how many of them dented? 0. You know how many had the sapphire scratched? 0. Broken or cracked? 0. I'll say it yet again, but I've fallen of bikes, been hit by cars, been to concerts, played sports, worked out and been tossed around by serious waves while wearing all of them. The worst that happened to any of them is scratches, and the worst place that's going to occur is the bracelet. You gonna put a bumper on the link bracelet too? Scratches DO build character. They're a visual reminder of everything you've been through. It's also called a patina. In 4 years of wearing my current daily go to, if I look close, there's scratches. From a normal distance away if you and I were having a conversation, the watch looks brand new. You couldn't see a single scratch.
4. In the case of stainless steel and gold, you can polish scratches out. It's very easy to do. If Apple won't do it (which would also be a joke), you could take it to most jewelers who would. When I have my watches serviced every 4 years I figure out if I want to have them polished and come back looking like new. Some I do, some I don't.
I do subscribe to the idea that you shouldn't care what others think about you, so take this with a grain of salt, but the day I see a person wearing an Apple watch with a case or bumper, my sides are going to hurt from how hard I'm going to be laughing. You've completely missed the point. What are you even buying an Apple Watch for anyway? You said yourself it's much nicer looking than any other smartwatch, so WHY would you want to cover that up? Who exactly are you covering it up for? The person you plan to sell the watch to in a year when it's becoming obsolete? Come on dude, just chill out. Live life, enjoy the design of nice things you purchase and don't be that ******* that covers his (probably awful) furniture in plastic.