Encounters and Random Encounters

[Tielc]

I purchased Curse of Strahd, and I've noticed that for nearly every random encounter, there's also a matching encounter. Is there any reason to keep both?

[Zacchaeus]

I left all of the original encounters in when I updated CoS to include actual random encounters (the module was developed before random encounters was a thing).

The reason I did so was just in case I missed something and therefore broke a link. So in essence there isn't a reason to keep the originals. But you'll never see them if you just use the links from the story or tables. You're only seeing them because you're looking at the encounter list.