Nah you not, i too use to think like that. Hence when you go thru my older photos you will see they not "tagged" at all. I started using watermarks after i created my blog, which is now a default feature on my lightroom when i export the image as the web knows no boundaries nor shores. So it's very easy to just grab an image(esp mine cos my theme posts High Res Photos), copyright it and make a few bucks off it without your knowledge. I also use it as it as some form of "marketing" & recognition, you wont believe how many people know the watermark more than the man behind the "Leboshmoove" watermark. Then there are agencies or individuals who constantly ask for my portfolio before a shoot, need i say more?
Sorry for bombarding you if words if i did, it's a sickness that i am yet to find a cure for.