I know it's common belief, but I'm not convinced that the concept of Cara-pils adding dextrins and reducing fermentability is all that it's made out to be (in the case of partial mash or all-grain brewing). I've experimented with different percentages of Cara-pils (from none to 12%) in same or similar recipes and saw no difference (within the margin of error) in wort fermentability. (I should also state that I didn't see a correlation between foam/retention and increased amounts of Cara-pils either).
It seems to me that long-chained sugars (dextrins) provided by Cara-pils would get broken down in the mash to fermentable sugars... either by beta-amylase alone or first by alpha-amylase, then beta. This would all be dependent on the mash type and temperature... i.e., a single infusion mash at a relatively high temp (e.g., 156°F) would leave more dextrins from the Cara-pils than a lower mash temp or with a decoction mash.
An example of this is a recipe for a helles in the book "Bavarian Helles" by Horst Dornbusch that calls for 20% Cara-pils... and a typical FG of a helles is in the 1.010 range.
In any case, Cara-pils can add a subtle/delicate maltiness (which would be more noticeable in lower-hopped beers) and lighten the color of a beer, since it is one of the lightest colored malts... for example, if you wanted a very light colored beer while still keeping plenty of malt flavor.