I don't treat it as an action show, really. It's sorta character drama with a great setting, but damn the MC is hindering my enjoyment.
The thing is, it's not the uselessness that's grating(there are lots of anime character that are useless as well), but the lack of self-awareness and just made her/him/it. I mean people rag on Shinji for being useless m, but he actually get shit done AND has plausible reasons for being useless at times, while Phos is straight up useless and annoying/bratty without even being funny (as it is played straight). Makes it harder to root for her to change as a viewer (atleast for me). NHK also has a totally useless MC huh fails, but it serves a greater narrative.