First, let me apologise for posting here...because I do not practice Theravada.
I hope, however, that my comments will be taken in the spirit I intend them.
My Thai wife has been going through a very stressfull time. Her father, now deceased, had three wives.
His first wife, the one she refered to as her "big mother" died a little over a month ago after a long illness.
Now, her "third mother" is ill, and probably will pass away soon. They were both in their 80's (my wife is 63 years old).
Add that to the flooding we are currently having here in Bangkok...and you can understrand the stress she is under now.
About a week she asked me why was there so much suffering and pain...impermanence... in the world.
I didn't have any real answer...but later while meditating it came to me clearly.
Consider this:
Without suffering, pain, impermanence, and such...why would a sentient being abandon his/her life in this world and start to seek a Buddhist path?
If there was no suffering, there would be no reason to abandom the (illusionary) pleasures of his/her life, would there?
And if they did not start that path, then how would they, in the fullness of time, ever reach release from the cycle of death and re-brth?
When you understand this clearly, you see the "purpose" (I hate to use that term, but I don't know how else to describe it) of suffering and impermanence.
Or you might say: (poetically)
For this purpose, and for this purpose alone, did the Buddha enter into this world;
to spin the Great Wheel of Dharma,
that by this all sentient beings might come to understand that Dharma.
And by that understanding they might gain release from the cycle of birth, suffering, death, znd re-birth.
For that purpose, and that purpose alone.
If you think carefully about that statement...then answer this question?
What is it, this YOU, who you say is afraid of "impermanence"?

In Quietness is the beginning of all things.
When I was younger I used to think I knew all the answers. Now I would be happy to feel I could ask just one intelligent question.