Jane Street Business Development Program interview questions

I feel that the whole process is a waste of time. I went through three rounds of interviews. First round is an excel task, second one is a phone interview about brain teasers, the third one was with two interviewees, they described a process and asked me to draw a flow chart about the process, and then they asked me some questions about the chart. At the end of the interview, I asked for feedback, the interviewee said I did a good job. I draw a clear chart, and clearly answered all the asked questions. Few days later, when I emailed HR to ask for updates, I was told that they would not move forward with me, and no feedback at all. I know the salary that the company posted online is high, but I feel they do not really want to hire anyone. Generally, do not waste your precious time on this company.