You can only keep up the three copies of a card in a deck
yeah but why break it?
"hurr it can be used against me!"
not it cant, why would he give it away? and if people resort to criminal acts to get those cards why not just shoot them then since hes the richest man in the yugiworld?
he had to be absolutely sure that no one else could use his waifu
Wasn't that also not really "Kaiba" at that point? He was taken over by his negative emotions or some garbage.
It was really Kaiba.
Kaiba was an orphan that was abused into villainy by his stepdad. After losing to Yugi in the Death-T games, he was "mind crushed" and given the opportunity to put himself back together without all the baggage, so he was Still a jerk, just not blatantly evil.
In the 4kids dub the clown imposter from Duelist Kingdom was explained as the evil remnants of Kaibas mind.
That's interesting guess people being assholes is too mature for 4kids ---