@Cristina-And-Daniel0 Apparently it's just a way you can add fees for your own use - from a guests perspective they are hidden under other fees:
The linens fee is added to the cleaning fee. All other fees are rolled into the nightly price for guests when they book.
In Vienna, we hosts must pay a 'local tax' or a 'city tax' of approx. 3%. I just discovered that we can add these additional fees as well and perhaps it would be useful to utilize 'community fee' or 'resort fee' for this purpose. I think it could work nicely for accounting purposes.
With regards to linen fee, I only see the option to charge per reservation, but in reality, it would be much more effective if one could charge per guest.