There's no real harm, except potentially to the up-and-coming designer, who is signaling something about their design process by writing something like this. Wikipedia has a lot of design constraints that other sites don't have. A big part of the job of being a professional designer is discovering and navigating design constraints. So when you pick Wikipedia as your "bucket list" portfolio spec design example, you might want to be careful that you're not communicating something about your process (specifically: obliviousness) that you don't mean to communicate.
Spec designs are fun to read and while I'm not a designer and have no business offering career advice to one, I'm happy to encourage people to keep doing them so I can keep reading and snipping at them. But there are safer targets to pick than Wikipedia.