You'll need the basic Pokmon in play before you can evolve it into Exeggutor
Tools like Beckett, 130 Point, and Card Ladder give you the market data needed so you don't buy collections at the wrong price or underprice your own inventory
Aside from the beautifully-treated artwork, the cards have value in how they affect the game itself, depending on what strategy you use
Considering that some regular Pokemon ex can survive these attacks, I'm finding it hard to believe that they're worth 3 points on paper
It does mean that if cards like these are the only way your deck can win, you probably need to examine your underlying strategies to assess why they arent pulling their weight
Later releases tempered Claydol's abilities, and it never regained the same importance as those earlier years