Reverse in the flare was very useful given Trident high approach speeds. But Edi 31/13 was perfectly usable without it (as were all the other ex-RAF 6000 foot runways) provided it wasn't wet. Gibraltar had the additional frisson of having a particularly damp overrun.
Having flown aeroplanes in multifarious ways (manual throttle/auto throttle/diy throttle/get-the-other-chap-to-do-it) - I've always found it slightly amusing that some think their virility/feminity challenged if they don't handle their own throttles.
Autothrottle in manual flight only works if attitude is accurately controlled (otherwise it hunts). Quite liked the Tri system of asking for power settings as it discouraged over-control of power and meant the engines were being properly monitored - particularly on landing. It was perfectly possible to fly a fixed power approach on Trident (as with other aeroplanes) by playing the drag curve.
Unlike the other marks, the T3 had a tendency to skip on touchdown. Using reverse in the flare not only meant the engines hadn't fully spooled down (as previously pointed out) but also ensured a component of the thrust was ensuring good contact with the runway (no skip). Curiously, landings with full reverse thrust could often be very smooth - although the psychological effect on the nervous passenger can be imagined.