The word "destynacja" has been in use for some years now
I absolutely agree; it has been in usage for eons, as far back as I can remember. Perhaps this fragment from "Poradnia językowa" explains it well (my translation with some abbreviations):
The word "destynacja" - as used in today's tourism related texts, meaning "miejsce przeznaczenia", "cel podróży" was already defined in "Słownik języka polskiego PAN" (Dictionary of Polish Language by Polish Academy of Sciences) edited by W. Doroszewski, published in 1958-1962. It included many older, outdated words. The noun "destynacja" was one of these and it meant "destiny" form Latin "destinatio" - fate, order.
Doroszewski's Dictionary gives the following example of use of that term contained in the eighteenth-century letter written by Stanisław Trembecki:
"Gdyby na koniec podobało się WKMci te pokorne prośby moje odrzucić, wszelako ja według
pierwszej destynacji i do wód, i dalej się puszczę, choćbym miał z brudnym służącym we dwóch na jednym koniu tę odprawić podróż."
Futher, the following quotations were given in relation to the verb "destynować":
Joachim Lelevel: "W trzech pokojach trzy stoliki z bostonem, jeden pokój
destynowany dla młodzieży"
A. Naruszewicz: "Dwaj młodsi bracia [...]
destynowani byli do stanu duchownego."
That dictionary also notes the noun "destynator", being generally an indication of a person to whom something is intended to, and specifically - a recipient of goods designated by a sender.
Before that the noun "destynacja" was mentioned in "Słownik języka polskiego" edited by J. Karłowicz, A. Kryński an W. Niedźwiedzki (a.k.a. Słownik warszawski), year 1900. In those days the word was considered to be little used, although the dictionary has several genetically related forms, such as "destynowanie, destynować, destynator".
The very word "destynacja" was shown with a quote from Tadeusz Kosciuszko: "Armaty, jeśli te są, które mają
destynacjądo Grodna, niech idą jak najspieszniej", and from there the reader was pointed to the noun "destynowanie", and from there in turn to the verb "destynować" - to allocate, to designate: "Był to znak woli i Opatrzności boskiej, że mnie
destynowała na wielkie rzeczy. Nikt do tej pracy nie chciał być
destynowanym."
The noun "destynacja", like many other foreign words, has been now borrowed again to the Polish language - this time from English.