That's a little different. Wifi is an invisible feature, and it can become disabled through no action of yours. Cameras are physical, so you can make it really obvious when it's enabled and when it's not. You just look for the physical obstruction. Apple's first iSight camera, for example, had a cool leaf shutter that you opened or closed by twisting it.

I know lots of people who have had trouble getting their wifi to work. I don't know anyone who put a piece of tape across their camera and then couldn't figure out why their camera didn't work.