Although Nellie did not ask a question, I feel there is a question behind her comment to How You Slip Does Matter that I want to address …
Nellie wrote:
I remember when I first started lace knitting and was on a shawl group.
I mentioned that I like knitting the chain edge. I was sharing this with others.
I felt that I was scolded by more experienced lace knitters.
Their opinion was that the chain edge was not suitable for shawls. If I remember correctly, they said something about distorting the edges.
I don’t understand why someone (even a “more experienced” lace knitter) would scold you about your preferences. I am sorry you were subjected to that and hope it does not put you off.
As you can see in the close-up in the photo for Chain Stitch Selvedge of the Lace Cable Bookmark, the chain stitch lays sideways and therefore is not in the same orientation as other stitches. So technically that could be interpreted as distortion. But does not make it inappropriate as such for shawls.
Also, the slipped stitch spans 2 rows. When that stitch has been knitted on the previous row, and now slipped purlwise with yarn in front, the stitch height can expand to the full 2 rows over which it spans. (assuming you are knitting at a loose lace tension rather than snugging up your knitting unnecessarily at the edges!) However, if any one of these elements of the “formula” is not met, you can result in a twisted stitch, or a stitch for which the height is otherwise less than the 2 rows; thus causing the edge to distort because eventually it is shorter than the rest of the knitting.
There are many ways to treat the selvedge stitches of lace edgings, and lace items in general. Some methods are preferred for their function (e.g. stability vs. stretchiness and how they hold up to wear and use). Some are preferred for their aesthetics. Compatibility of both is the balancing act of design. Discerning which we want to use when and where is what helps us increase our skills and makes are knitting distinctive. I will be revisiting and expanding on this in the future.