AKA How do games keep track of your life total?
AKA how do you know when you've lost?
Yu-Gi-Oh starts you off with 8000LP which is comparable with Magic the Gatherings 20 Life, the problem I think is that both of these rely on an element outside of the deck be it a phone, a calculator or a D20 there's always something else to carry around. Other games have tried to get around this though, let's look at them now:
Duel Masters : Cards from your deck as shields, lose on a direct attack.
Harry Potter : Damage taken results in milling yourself, first to run out of cards loses.
Pokémon : Once your opponent takes all their prize cards, you lose (lose 6 battles).
Dimension Zero : Direct attacks add mana, seven of these mana and you lose.
So the question becomes, how do you want to keep score? Is it such a big deal to have players keep count on their own or is it better to be self contained?