I asked it to tweak the fonts/colors of a very very simple static page and it blew through $35 (which is a lot for me lol; it's 10 days of my monthly codex plan).
They cannot even move 10 existing lines of code around without breaking it in the process half of the time.
I very much doubt they are up to the task of implementing any sort of plan with a reliability that allows to complete the work faster than writing the code by hand.