Yes, essentially they aren't linked, they are independent profiles that you can just easily swap between.
I've made a comment about the potential confusion before as it seems people have different assumptions as to what the functionality is to the point where yes, I believe clarification is needed but "user" from the client perspective I think is even more confusing. - Joplin 2.8 is available! - #19 by Daeraxa
I think it is interesting that people have very different ideas about the multiple profiles.
I see it as a way to enable isolated profiles that I can do what I want with. If I want a device at work with only my work data, a device at home with only my personal data and a third device with both then it enables this just fine where my primary goal would be that certain devices simply don't have access to data stored on others at my choosing.
However it seems that others see this as an additional "level" of categorisation where keeping everything under a single sync is important, the "sandboxing" isn't essential and therefore expect any profiles to be synced to any new devices they set up.