It has nothing to do with the spring, nor does it matter as you say at Max Continuous. Where it matters is on start up and shut down, the strap pack in the T/r get beat up pretty bad. It's good housekeeping.
Do you always do ONLY what's in the Flight Manual? There's more to operating an aircraft than what's printed by the manufacturer. You go ahead and leave your pedals, makes no difference to me, but our DOM who's been wrenching these things for 25yrs is adamant about it, as are those in other operations - good enough for me.
There are lots of things omitted from Flight Manuals that are just a good idea.
RH