Indeed the SolarCoin method is fairly unique, and while at first the adoption rate was slow, it seems to be accellerating, not ony with individual small holders but large entities like ACWA Power and Access Power going public in 2018 about their claims.
We are also seeing many other businesses beginning to adopt, I wrote about it here https://steemit.com/solarcoin/@scalextrix/lots-of-good-news-coming-from-solarcoin-recently