To clarify, Candy can deal massive amounts of damage if there's no defender. The best turn to use it on is turn 1 as most human players would discard everything for more mana. My intention was to put the player in a position to decide to either start with a massive hp advantage, block potential damage or gain one more mana. But against my computer player this never really was a thing to be aware off.
Sending home is removing the card from your hand entirely. It doesn't go into the discard deck or reshuffled. The benefit is to make the deck sleeker, so for humans, they can draw more Neko cards to build up to 10 Mana faster and have the priestess drawn more likely in the turn following reaching 10. For elves, a couple of cards gain hp on sending home, plus you draw the Archer card more often leading to faster victories. But for the difficulty level I had the game at, I agree it seems to not affect the gameplay enough to warrant doing it often.