Why is FIRST_CONN_PARAMS_UPDATE_DELAY set to multiseconds in most examples?

In most of the examples the FIRST_CONN_PARAMS_UPDATE_DELAY define is set to something like 5000ms. Is there a reason it needs to be that long? I would like to switch to a lower power connection scheme (>45ms connection interval with slave latency of 8) as soon as possible after the connection is established. Any guidance on shortening the time before connection parameters get updated?