The phrase "than disposables" is a comparison between two things. In this case, it means that cloth diapers are more environmentally friendly and cost-effective than using disposable diapers.
Sentences with «than disposables»
These facts alone are a very good reason to start using cloth diapers rather than disposable diapers. (momtricks.com)
And from experience, cloth works so much better than disposable diapers! (babycenter.com)
Yes, in the long run they are much cheaper than disposable diapers, but that initial investment can be very steep. (babytooshy.com)