Those are 2 different ways of using a emunadn, one is for keep a not updated sysnand, other is as a extra protection from ban
You don't need to remain in a low FW to run emunand, Fusee Gelee works in all versions. you can have a "unthethered" in any version whit a modchip(that acts basically like a dongle but is inside the switch) rebug team is making one. is soldered hardmod.
Technically you can have both features by having 2 emunand, one clean and online and other dirty and offline, and keep a low sysnand, but im not sure if going online whit a clean emunand is risk-free, so im waiting to see what happens to others in that aspect before jumping to wrong conclusion
Answered my question, thanks