For a lo-co airline with short (25min) turnround times, brake cooling after landing with idle reverse can be a significant operational factor.
So whilst brakes may be cheaper than engines (though I suspect brakes are replaced somewhat more frequently), if your company requirs short turnrounds then consider that using only idle reverse almost doubles the brake energy.
Check the tables for your aircraft type, and always make sure that your brakes are cool enough to cope with an RTO on the next sector!
Of course, if the runway is really that long then manual braking can be used instead of autobrakes and braking requirements then minimised too.