Dan, I haven't seen any airbus manuals, but I doubt they say to use "max" thrust for all landings.
On small jets, use of reverse thrust can poses some controllability problems, and hence those pilots are hesitant to immediately go to full reverse on landings. Typically, in these cases, the pilot concentrates on applications of brake, and steering of course. Reverse takes a much lower priority, and the usual sequence of events are to first get reverse thrust deployed at idle, and then slowly increase power in a controllable way. And often the aircraft is well decelerated by the time full, or close to full, rev thrust is attained.
And here's one to think about. With any crab on, eg for a slippery runway with a cross wind, then the added use of reverse thrust will actually pull the aircraft towards the downwind side of the runway. When this starts to happen, immediate reduction of power, among other things, can be required to keep the aircraft from drifting off the downwind edge of the runway!!
Yes, you could say rev thrust is more "efficient" at higher speeds, I prefer to think of it as the reverser dissipates more energy when used at higher speeds than at lower speeds, hence less brake wear.
The aircraft type/engines can have different speeds to be out of reverse. For example, for some, only idle thrust with reversers deployed below 60 kts, and some even allow an appreciable amout of thrust up til the time the aircraft has stopped.
Hawk