I guess some people try to do it just to see what they can do. Others do it maybe as a party trick - others to try to impress people. I try to memorize just the first few and I do that since I use it. I think I recall that
pi ~ 3.140159 ...
Okay - just checked - seems I was wrong. It's
pi ~ 3.141592 ....
Oh well. No party favor for me. :-)