For instance, Alyssa mentions in this post that most emulated games will need at least 16 Gigs of RAM at minimum.
In addition, native ARM games on MacOS don't have the additional overhead of emulating a different CPU architecture and Graphics API.
However, that doesn't take away from this emulated support being an amazing achievement.
That's because the RAM is shared with the GPU and most of these games would require a GPU with at least 2-4GB on top of the normal system requirement to have at least 8GB. So, 8GB of RAM would be cutting it close on a mac since part of that would have to be sacrificed for the GPU.