You can't cheat him into play from your hand with Kaalia, and you can't find Clive in your deck with Terra: They care about enchantments, and Clive's front face isnt an enchantment
Put your opponents in a sticky place Winnie the Pooh makes a strong showing across Rise of the Floodborn, with the Hundred Acre Woods most famous resident and friends popping up across the new Lorcana set
They won't stop the Human you find from entering the battlefield attacking
He can be a real thorn in your opponents side if you can quest with him on turn three, and block potential challengers
Shiftable characters provide you with a way to get stronger characters on the board for a cheaper cost while still having other low-cost characters in your deck that can pave the way for them
Many items wont be useful until the next turn, but there are many which give buffs just for being on the board, or whose effects activate when played