Side Decking Cards

Okay so basically, I am wondering about some cards, and if they are worth siding.

Gravekeeper's Watcher
DARK
Spellcaster
Level 4
1000/1500

During either player's turn, when your opponent activates a Spell/Trap Card or monster effect that could make them discard when it resolves: You can send this card from your hand to the Graveyard; negate the activation, and if you do, destroy it.



Now this card seems to be perfect to counter Dark Worlds During key points in their strategy, and can even stop Dragged Down, which can easily ruin your otherwise good hand.

I'm not sure if it's worth siding, and was wondering what you guys thought?
For gravekeepers, he seems to have some nice potential, since he is easily searchable with Gravekeeper's Recruiter, and I can add him back to my hand with Gravekeeper's Stele.

What do you guys think?

Not worth it. It's only good against Dark world, and they have too many spells for discards, and thus it's not good,

I personnally like Imperial Iron Wall . But in the end, it all depends on what you're playing with.