One issue is that you only know how gusty it is on approach after the event. The atis and tower winds often bear little resemblance to the winds at a thousand feet.
The arm mode is extremely useful in missed approaches, but statistically I have gone around way less than 1% over the last ten years as a captain on the 737. But co-pilots chasing the speed is pretty much a daily occurrence. It is usually way too high rather than too low, which is a problem if you operate to shorter runways regularly.
Equally relying on the auto throttle to dig you out of trouble is not foolproof as the Turkish airlines crash in Amsterdam demonstrated.
I would have no problem with being told we should try and use arm more. But based on my experience I still prefer all off or all on for the 737.
The point about rote learning is a interesting one. New pilots have to learn the SOPs and apply them. It is only after they have gained enough experience that they can understand why they are doing something.
Some of our guys think they know a great deal more than they really do when released to the line. The reality is that a decent level of experience is about 1500 hours by which time they often have something bigger and shinier in mind and move on.