Yes, it's a good thing.
I use 2x4 walls with r-13 fiberglass, then 1" eps as sheathing with diagonal steel bracing, no osb. This gives me 5-18 and they give me r-1 for the air space between the eps and the brick.
I just got done taking all the cutouts from my windows and doors and cutting them up and putting them in the rim joist area. I have yet to put the eps on the rim joist on the outside, but I have 2" on the inside. Later I'll put R-19 fiberglass on top of this. Anyway, the windows have yet to be insulated in the basement and there are places where the rim joist is above the sill plate and you can see light yet. It was -20 fahrenheit 2 nights ago and the basement temperature was at 26 with only the floor deck above and the sheathed walls, sheathed roof, but no sheetrock, etc.
I thought that was pretty good given the circumstances.
The heat loss calculation is 25,700 BTUH for 900 square feet up and the same in the basement (townhome). They are requiring r-50 in the attic nowadays.