Here we go; the Lotus Sutra is powerful and the reason is contained in Ch. 21 the Transmission chapter:
"In general, all the Dharmas of the Thus Come One, all the sovereign spiritual powers of the Thus Come One, all the secret storehouses of the Thus Come One, all the extremely profound deeds of the Thus Come One are all proclaimed and revealed in this Sutra.http://www.buddhistdoor.com/oldweb/reso ... otus21.htm
Nichiren Buddhists are familiar with this power, chanting the Sutra and the title, the Daimoku, It has been abused to get worldy things which is just wrong; the point is to practice to reach buddhahood.
The Sutra proclaims that Shakyamuni Buddha is eternal, that the other buddhas are his replica bodies, that all previous paths are replaced by the One Vehicle, that all things are essentially equal, that beings can attain buddhahood. Not just people, animals and even grasses and trees. Also it contains the buddhahood of a female, the Dragon King's daughter, so important.
There is a lot in the sutra, Zhiyi didn't write books about it for no reason, I think other buddhists just think of it as a teaching text, not a text that can really change
things, whilst Nichiren Buddhist do know this.