Why have Katakana option if the answer will not be accepted

i’m a fan of this script.

personally, i’m allergic to shift and capslock, so katakana coming out when it’s not supposed to isn’t a problem for me, but i appreciate the visual cue for which type of reading i’m being taught for each kanji. (and the script puts you on auto-capslock when answering for kanji whose on’yomis are expected.)