The Bombardier Dash-8 Q400 FCOM says (emphasis mine):
The autofeather system provides automatically initiated propeller feathering following an engine failure during take-off, and power uptrim of the operating engine (Figure 12.22-5). Autofeather is selected on for take off only, using the AUTOFEATHER switchlight on the engine instrument panel.
It only says autofeather should be used for take off only, but fails to explain why. I would assume autofeather would also be useful when landing. The uptrim (automatic power increase for remaining engine) might not, but it is independent anyway:
Uptrim is triggered (regardless of autofeather selection) [...]
Why should autofeather not be selected during landing?