Welcome on board. Here are the answers to your questions:
1.Roon can’t touch your files, including playlists. If you want to edit a playlists which wasn’t created in Roon you need to save a local copy first. To do this you need to follow these steps:
Open playlist details page
Press the Pencil button in bottom right corner
In appeared pop-up press ‘Save A Local Copy’ button.
As for the ‘global playlists’ this means that if you have more than one profile in Roon, playlist with such status will be shown to all profiles.
2.This is not a one-time import, Roon tracks changes of your iTunes library on a regular basis.
3.Since Roon can’t modify your files, there is now possible was to edit tags inside of them. All changes made in Roon will be saved in its database.
So would it be wise to continue using iTunes as a management tool, while using Roon as a player and viewer? And is this read-only approach a design choice, or a current limitation that will change with later releases?
If you don’t care about playlists which were created in iTunes, I would recommend to start from scratch in Roon (but read this FAQ article first ). Yes, it is a design choice.
I do care about them. Me and iTunes go a long way back, so there are a lot of memories there from different events. But there’s nothing keeping me from leaving, as long as I can take my carefully curated playlists with me. I guess I can create them in Roon instead!