What was so significant about Jacob's well...?

Jacob had property in this vicinity. (Ge 33:18-20; Jos 24:32; Joh 4:5). So Jacob likely dug it or had it dug, perhaps to provide water for his large household and flocks, thereby preventing trouble with his neighbors, who doubtless already owned the other water sources in the region. Or, he may have needed a better and more permanent supply of water when other wells in the area dried up.