The argument being made is that the distinction between an FPGA and CPU is irrelevant to determine whether something is emulation.

An emulator accelerated by an FPGA is still an emulator and a CPU simulating a console at the circuit level is no different in accuracy than an FPGA doing the same thing.

The main difference is the experience, where the FPGA can offer an experience closer to the original than a CPU running an operating system can, especially for older consoles. Not because of a difference in emulation accuracy, but because the user experience is different.