ingにしなかったところが今回のポイントみたいですね。実際に他の分離領域に転送しているわけではなく、そういうことができることを示すものだから「able」にしたと。

The idea was that this would superficially match parameter modifiers like consuming and borrowing. But, this ignored that we are not actually transferring the parameter into another isolation domain at the function boundary point. Instead, we are requiring that the value at that point be in a disconnected region and thus have the capability to be sent to another isolation domain or merged into actor isolated state.