Relevant is as pointed out (during the 'high speed' portion of the landing roll (regarded as above 60kts)). Best thing to do is look at how long your landing roll will be (from your performance charts) and then you can work out if you are going to be in the 'mid' or 'stop' end portion for the runway you intend to land on. If you will be then they are controlling, just as the T/D zone is.
On the 737 we check the autobrake stopping distance for the configuration and decide on a setting suitable for the conditions. Many factors can come into it, but for instance if the stop end was out of limits (if it were controlling), then we may be able to up the autobrake setting to pull up quicker and hence not enter the stop end and thus be able to disregard the stop end RVR and therefore be able to make a landing on said runway!
Hope this helps.
PP