If you want a disc wheel just for the bling, go for it. For actual street riding though they're pretty silly. If you find one it might be expensive, heavy, or fragile. Also most of them are tubular which has it's tradeoffs.

Here's mine, it was super cheap at the cost of being extremely heavy and only freewheel threaded, almost totally useless overall.



There's a photo of a Panasonic keirin bike with a polished aluminum disc which is absolutely beautiful (aside from the hideous geometry of the frame). Aluminum discs are pretty rare and valuable though.