The best casts are "canted" to the outside but IMHO not sidearm. It introduces too much turbulence over the length of the total cast.
Even irregularity between the shape of the back cast loop causes resultant turbulence in the forward cast even if the first 70-80 feet is fully energized with good form going forward, the last portion of the cast will telegraph all of the shape transformation that the loop form went thru to get from back to front.
IMHO, the best medicine is to refine the best possible loop form with a comfortable arm angle keeping what I call the "driver" (portion of energized line from tip to wedge) tracking on a vector that is slightly closer to the caster than the "trailer" (the portion of line past the wedge that is coming along for the ride) and exactly 180 degrees from back to front. The less turbulence the better the cast.
Sure in practice throwing a longer side-armish stroke to poke a wedge into a tailwind is good fishing technique, but the best distance casting comes from clean technique in the ideal plane between vertical and horizontal.
Sidearm technique is something you'd consider for placement under obstructions or in some cases to tuck a cast under the wind; although I use line design and double haul energy with a lower directed stroke to achieve the same result. In saltwater I have found no need to resort to it in my experiences, your results may vary.