I had a side-to-end resection in 1978. I had waited until I had a full obstruction and had been battling a high grade partial obstruction so the area above the obstruction had stretched out quite a bit. I was told the side-to-end anastomosis was to allow for less intestine to be removed. They only had to resect the actively diseased area. Ever try to join a 1 inch hose to a 3 inch hose?? That also allows for a wider anastomosis so theoretically at least it will take longer for scar tissue to cause new narrowing.
This is sorta the idea behind strictureplasty as well. IF there is narrowing due to scar tissue and disease in the area is dormant strictureplasty allows widening of the narrowed area w/o having to remove any intestine. At least this is my understanding of the side-to-side, side-to-end and strictureplasty surgeries.