The most important thing is that many emulators are not modeled in such a way as to offer cycle-accurate results, whereas this is easier to achieve with FPGA im

The most important thing is that many emulators are not modeled in such a way as to offer cycle-accurate results, whereas this is easier to achieve with FPGA implementations of devices. You can see evidence of syncing issues from emulators just from reading things like the Dolphin emulator's update blog and how many times they're dealing with them [1]. This is a double-edged sword of course, as a cycle-accurate reproduction of the original hardware doesn't give the same opportunities to offer modern improvements like arbitrary scaling, updating textures, and makes state saving more of a challenge. 1: https://dolphin-emu.org/blog/2022/09/13/dolphin-progress-report-july-and-august-2022/#50-16901-flush-command-buffers-after-multiple-efb-copies-by-tellowkrinkle (the linked example also highlights how variations in hardware memory architecture present real hard challenges for software emulation, which would be simple to overcome in an FPGA)