>>57563942I believe its mostly due to her being one of the main girls in the anime. Mallow or Lillie don't show feet, or at least not at the start. Combine this with her portrayal in both anime and games, its no wonder she became the star of attention.
Also, she just looks cute in her flip-flops, and like
>>57563956 said, her feet are just well drawn. I also like that her flip-flops are slightly bigger than her feet.
And yeah, Acerola, Olivia and Lusamine (sorta), show feet, but Lana is also one of the earlier girls and was prominent in the trailers too, compared to the others where you meet them mid game.
>>57564525This is a Lana feet appreciation thread