Drawdown pass-through
With one leader, your drawdown is their drawdown, undiluted. A 40% peak-to-trough decline in their account is a 40% decline in the mirrored portion of yours, arriving at exactly the moment you are most likely to abandon the strategy.
A basket does not eliminate drawdown — correlated leaders can decline together — but it removes the single point of failure. One leader's bad month is a fraction of the book rather than the whole of it.