Client intraday credit usage is the measure that is derived by comparing a client's peak daily intraday overdraft to the established credit line. This measure is crucial as it provides an indicator of the necessary liquidity required to support a client's business activities. It helps banks to understand the client's credit usage pattern and manage their credit lines effectively. This measure is particularly important in managing the risk associated with intraday credit and ensuring that the client does not exceed their credit limit.

Choice B is incorrect. Payment throughput refers to the total value of payments that can be processed by a system within a given time period. It does not involve comparing a client's highest daily intraday overdraft to their established credit line.

Choice C is incorrect. Daily maximum intraday liquidity usage refers to the maximum amount of liquidity used by an entity during a single day, which may include various transactions and not just overdrafts compared to credit lines.

Choice D is incorrect. Total bank intraday credit lines available and usage would refer to the overall capacity of the bank for providing intraday credit and how much of it has been utilized, rather than focusing on individual client's highest daily intraday overdraft in relation to their established credit line.