hiii anjali...gud to see u again after a long pause....chal main hi answer karti ho tera yeh....
woh isliye so that they have the perfect muzic n dance beats ....for example take the song "jane tu mera kya hai" from film 'jane tu ya jane na'.....when alisha performed on that song it was a total remix song ...that song has nuthing much to offer but when remixed it has much to offer (dance beats n swell syncronized) and she danced jhakas.......
[YOUTUBE]http://www.youtube.com/watch?v=US6juzq-jPQ[/YOUTUBE]