A Money-Back policy is structurally an endowment that returns a portion of the Sum Assured every few years, instead of waiting for maturity. Typical schedule: 20% at year 5, 20% at year 10, 20% at year 15, balance + bonuses at year 20. The death benefit during the term remains the full original Sum Assured regardless of survival benefits already paid.
Money-back plans appeal to buyers who want periodic liquidity, but the implicit XIRR is usually lower than a pure endowment of the same term — the insurer pays out earlier, so it earns less investment return on your money.