If one is performing a shortfield landing and equal braking action is a must for directional control, application and testing of brakes may be very important, depending on a variety of factors that include brake type and condition, temperature, meteorological conditions, etc. Just as previously stated.
Some aircraft have no ground steering capability but brakes; brakes are critical not only to getting stopped in such cases, but aircraft conrol. If both brakes do not apply equally during the landing, aircraft control may be lost; brake application prior to landing in such cases is often critical.