Rashi writes that the reason the clothes were mentioned is because to the Egyptians they were regarded as being of greater value than their silver and gold.
Based off this, the Maharal in Gur Aryeh explains:
ויש מקשים למה כתב במעשה "כלי כסף וכלי זהב ושמלות", ואילו למעלה (יא, ב) לא כתב רק "וישאלו כלי כסף וכלי זהב" ולא שמלות, ורש"י פירש דשמלות היו חשובים יותר במצרים, ואין זה קשיא, דכאן מדבר מן המצריים, ואצלם היו חשובים, כי במצרים היו חשובים, אבל אצל ישראל שיצאו ממצרים לא היו חשובים כל כך:
And there are those who ask why it writes "Vessels of silver and vessels of gold and garments", and yet earlier (11:2) it only writes, "And they shall borrow vessels of silver and vessels of gold" - and not garments? And Rashi explains that garments were regarded as being more important/valuable in Egypt. And this is not a difficulty/question since here it is speaking as coming from the Egyptians, and by them they were regarded as being more valuable because the Egyptians thought of them as being more important, but by the Jews that departed from Egypt they did not find them important at all.
Therefore, in answer to your question, they only got these clothes because the Egyptians in their haste to make the Jewish people leave handed them all their greatest valuables, of which their clothing featured highest. However, the Jews didn't have any particular interest in them i.e. they took them but did not depart from their usual dress.