The second segment begins with Gears retracted. Thus, LGTU helps to retract gears, in case #1 engines fails, so that 2nd segment can start on time. In case if this feature was not there, then in case of #1 engine failure ( that is EDP system A ) the gears would take much longer time to retract. This would extend First segment and delay second segment, which would have an adverse effect on Take off thrust time limit.
I hope this makes sense!
Safe landings.
