If you’re unfamiliar with “pectin”, it’s a component in fruit that has natural congealing properties - meaning that it helps the gelling process required for jams and jellies to set.  Since different fruits have different pectin levels, the ability to isolate pectin and add it to jam recipes using naturally low-pectin fruits is incredibly convenient!  While it certainly is possible to make jam without pectin, it will require a substantial increase in cooking time, requiring you to stand over your stove top tentatively while checking the temperature of the jam mixture.