I don't see much of a case for most people to choose this over a Raspberry Pi Zero for running an emulator.
A Zero will most likely have a lower total price, is much faster, has vastly more memory and already has a lot of software support, all in about the same size as a Pico without an additional board.
I'm pretty sure that PicoGraham had ported emulators to the Pico mostly as a challenge and to show how powerful the RP2040 is — not to showcase it as a good option for running emulators on.
That said ... I am very tempted to get a board like this myself.