The main things were that they were relatively cheap and easy to make. Egg noodles were also actually part of Ashkenazi food traditions in Europe, going back to at least the sixteenth century text "Yosif Ometz" there are references to dishes similar to what we would now call lokshen or noodle kugel, using egg noodles or vermicelli. The noodle based Yerushalmi kugel goes back to the eighteenth century. Egg noodles were versatile, and they kept well. Lokshen making was considered an important skill for housewives. Claudia Roden wrote in "The Book of Jewish Food" that making lokshen "was once a cornerstone of feminine dexterity.” Women continued to make egg noodles when they came to America, and when cheap, dried noodles were introduced in the twentieth century they became even more common.

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https://www.joyofkosher.com/blogs/the-history-of-kugel/

https://www.tabletmag.com/jewish-life-and-religion/253083/ashkenazi-mac-and-cheese

The Book of Jewish Food by Claudia Roden