Sure but the way his company translates "a piece of cloth" into Japanese has the same literal meaning. There's nothing more meaningful, it has the same exact meaning. My opinion is that it's chosen to be deliberately simplistic - what could be simpler or less expressive than a piece of fabric with fashion - because it highlights how much innovation in craft and resulting form results from the simple description taken as actually an extreme constraint: nothing but a single piece of cloth. And then when you perhaps think about it more, or see some of the work, you realize the complex ingenuity of it, in stark contrast to the simplicity of the phrase itself. That contrast enhances the impact by highlighting the gap between the humble description and the complexity of the result which nonetheless remains faithful to that simplicity.
A more illustrative term might be more easily understandable, at the cost of elegance (in simplicity and constraint) and surprise (from your underestimation of the work based on its name). The term is branding.
BTW another reference is Maurizio Amadei's "One Piece" work. Here's an installation/artwork he did that makes it easy to understand: https://lucentement.com/blogs/journal/m-a-by-maurizio-amadei... He also has many products labeled "One Piece [X]" such as "One Piece Wallet" or "One Piece Boot", where they are made from a single piece of leather (never cut into multiple pieces) and with a minimal number of seams. He chooses a similarly simple term, "One Piece", with enigmatic effect.
