probably not relevant as I fly DHC8-Q400 now, and previously BAe146 and BAe ATP, but as a regional pilot, I tend to always have armrests adjusted to be relaxed and light on the controls at nearly all times.
I have them down for taxi, take-off, cruise and approach and landing. the exception is in rough air and strong crosswinds or low level turbulance approaches, where more abrupt or corrective actions are required.
Hence the term this looks like an "armrests up" kind of approach come about.
Living on a rock in the sea, the weather can be quite unpleasant, and full control movement is often needed on days you earn the pay. Good job the SLF don't get to see it coming.
With FBW and force sensing, it's important to separate the wrist action from arm movement, hence the Airbus SOP.
Hope the thread helps your understanding.