SX emunand can be used for (only one or the other):
1. Keeping your sysnand on a low fw, and using latest fw with emunand.
- No going online.
- No need autorcm to prevent burning of fuses since sysnand is on original fw. (You can boot to ofw without sending a payload, shut down normally from horizon, etc).
2. Going online with sysnand, staying offline with emunand.
- Not impossible for Nintendo to detect since emunand is stored in the user partition.