Canadian/American ops: Normal airline ops is to file the STAR as part of the flight plan. Like you said, the last cruise point is normally the first STAR waypoint. In this case the STAR is considered part of the "flight plan route" and, unless you are given a different clearance limit, they won't even mention the STAR.
If you don't enter a STAR, ATC will give it as part of a clearance - either when in contact with clearance delivery or at some point along the route.
In many cases you'll be well into a STAR before you know what runway you've been assigned (you can guess of courses, but I find I'm only correct 45% of the time) - so that's why it's beneficial to file it, in case you're cleared to a STAR waypoint...plus, it also helps improve fuel burn calculations.
Welcome to see if anywhere else in the world is different!