4 simple reason...
1) About the same reason why you want to put cloth diapers on your little ones :)
2) Health reason: Reduce exposure of our intimate parts to hazardous chemicals (dioxin, formalhydes, bleaches)
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3) Environment: Reduce garbage being put out to our mother nature
4) Fun: Coz it comes with multi colours and prints...
So, try it. And you'll love it.