I was thinking maybe it used less power when using it with battery power but now that I think of it, the main reason was because it looked like it could do exactly the same thing but I found them cheaper. I didn't understand the datasheet where it said "It is intended primarily for high volume consumer applications over the 0 to 125 degree temperature range."
https://www.mouser.com/datasheet/2/308/NCP1117_D-2307187.pdf
https://www.mouser.com/datasheet/2/308/1/NCP1117LP_D-2316911.pdf