Lifesteal SMP turns kills into extra hearts and deaths into lost hearts. Reach zero (or the server’s minimum) and you may be banned, stuck as a spectator, or forced to earn a revive—depending on the season rules.
Heart caps, crystal PvP rules, and anti-farm policies decide how fair it feels. Seasons are often short; joining late against geared teams is much harder than joining week one.
Read revive costs and farming rules. If hearts are easy to buy from the store, the mode has a safety net.