I have never heard anything about DAS other than that it works in the midwave IR band (not the near-IR). It will be heavily affected by IMC, as will other IR devices.
My opinion (and that's all it is) is that all-round IR imaging per se will decline in value as digital night-vision devices - such as the Intevac product used on the JSF HMDS - are integrated into helmets. It's a simpler and lower-latency solution to pilot night vision.
The fixed IR sensor approach does have some advantages - it works in zero light level and you can see through the floor - but I doubt that they are worth the disadvantages of lower resolution and latency issues. At that point, you can go to a simpler (possibly uncooled) IR sensor for warning and tracking.