I have an old tailoring manual where they say that you don't have to pad stitch the lapels when using heavy cloth.
But back in the days "heavy" meant a weight beyond even Sator's wildest dreams.
Jeffery, the cloth in your pad stitching video was relatively heavy (around 400gr.) for modern standards and you did wider stitches. Does that mean you'd do more rows of closer stitches if the cloth had like 8 oz. or less?
There is a difference between a regular blindstitch machine and a special pad stitch machine. Both do the same stitch, but the latter has a narrow horn, which allows the tailor to bend the lapel into shape. If the machine is well set it gives quite a nice result. But I agree, using it on very light weight fabrics might be difficult.
I had a picture somewhere of a coat in progress by Des Merrion, where he made just about 20 stitches on the lapel. Heavy cloth, light weight canvas (I think it was a 200gr. camel hair), but nice roll.