In my case, I often have a number of places to visit, but I have flexibility as to when to travel. So I may as well prioritise the sequence to achieve the lowest cost. This probably works best for leisure travelling, though in my case it applies for work travel.

Two other uses: for those just looking to fulfil their eligible flights requirement; also for those travellers trying to bolt on a cheap flight to a Club Europe single ticket to force a Saturday night rule.