The appeal is that any accidental changes to speech rate, keyboard echo, or any other NVDA setting will not become permanently locked into that profile.
Imagine this: you create a config profile for another language. now you switch to it, and want to turn character echo on to, say, type a series of numbers that need to be accurate.
As soon as you do that, character echo's state is permanent in that profile. It can never be synchronized with the default value, and you'll always have to adjust it.