no logic or rationale

Parshat Bo

At the height of the final plague, the plague of the firstborn, Pharoah calls Moshe and Aharon and tells them he agrees to let the Jews leave Egypt unconditionally. Before they leave, one of the things needed to be done is to acquire the wealth of Egypt. Moshe tells the Jews to go to their Egyptian neighbors and borrow/take their jewellery from them. In 12:36 the Torah says, "וה' נתן את חן העם בעיני מצרים וישאלום" - Hashem gave the people favor in the eyes of the Egyptians, and they lent to them [their jewels].

Why was this חן necessary? The Egyptians would have given the jews whatever they wanted at that point, just to get rid of them!
The חן does not even make sense - the Jews were just responsible for the decimation of Egypt and the Egyptians culmiating in the horrific death of a large percentage of Egyptians and all of the sudden they find favor and like the Jews? For Hashem to do that seems to have no purpose nor any logic and rationale!!??

Any ideas?