According to the source, the charkha or wheel was considered an exquisite piece of machinery because it was a symbol of human society which did not glorify the technology or the machines.
It could also provide the poor with supplementary income and make them self reliant.
He adopted the charkha because he wanted to glorify the dignity of manual labor and not of machines and technology, and wanted to promote a more decentralized method of production.
The charkha was seen as a tool to make the people self-reliant, both economically and spiritually.