And to be blunt revalidating by test is often cheaper and easier than doing so by experience.
I've done it both ways (crap wather and and unserviceble aircraft for the re-test). you will often find on here the re-test route being suggested to keep costs down - which it will.
you will also find a lot of comment about instructors who will treat the re-valiadation flight as a test whether you want one or not!
At the end of the day these requirements have just become another set of hoops to jump through to be allowed to continue flying legally. It would be interesting to see if anyone had any data which even suggested this made PPLs any safer............