Probably the only reason its still used a lot is because its so quick to complete.
Copied this from
http://www.webkit.org/blog/152/announcing-sunspider-09/
“December 19th, 2007 at 6:02 am Windows XP SP2, AMD Athlon XP 3000+ (2.1Ghz), 1 GB RAM13525.8ms +/- 3.4% – Opera 9.50 latest internal build16442.6ms +/- 0.7% – Safari 3.0.4 (523.13)19683.4ms +/- 0.9% – Firefox 3 beta 126424.4ms +/- 23.8% – Firefox 3 beta 232672.4ms +/- 1.0% – Firefox 2.0.1182053.8ms +/- 3.9% – IE 7″
Only 4 years ago Opera took 13.5 seconds & IE 7 82 seconds.
Today on my PC IE9 takes 132ms & the slowest browser was Firefox Nightly 11 only 189ms,
Is it still useful for modern PC’s running modern fast browsers ? I say no.
Mobile Phones & Tablets Yes.