It is not slow, it just captures packets in real time from your local flash player. But you are right, in many cases downloading can be done faster than in real time.

The benefits of RTMP packet capturing are the following:

• You can capture some protected streams that can't be downloaded
• Content providers can't detect that you record streams.

p.s.
Glad that I was able to help! Please do not distribute recordings, use stream recorders as your personal archiving tools only.