Originally Posted by RM-MN
It might be unnecessary but it won't hurt either. Carapils is the lightest of the cara malts and is known for increasing body and head retention without changing the flavor of the beer.
With a stout, what I would focus on is the level of roastiness vs the projected FG.
The higher the roast flavor the more need for a higher FG to balance.
How you get that higher FG is up to you. For a stout I would use crystal/cara malts with more flavor because I like big flavors in my stouts.
I do also like oats for body and residual sugars, cause they create a mouthfeel that is quite unique and pleasant IMO.