did a paid trial week, thought it went great, got a polite no anyway and still don't know why

Week went well by every signal I could read, good feedback in the daily check-ins, asked to demo to a wider group on the last day. Email a few days later just said they went a different direction, no other detail even after I asked directly. Not sure what a good trial week is even supposed to prove if it doesn't move the decision. Still logging it as a fine use of the week, just an expensive one for my calendar.