Albums and keywords are very similar features to organize the image archive. In both cases, images can be assigned any keywords and or albums. Both keywords and albums are organized hierarchically. I.e. the respective entries can be subentries of other entries. Thus it is possible that the same names can be used in different places.
So when is it better to use a keyword and when an album?
An Album works best when it is used as a virtual directory.
Unlike a physical directory on the hard drive, an image can be contained in different albums at the same time. Therefore, albums should be used to collect images that belong to a specific event. This can be a celebration or a trip.
Albums are also very useful to create a project. For example, when a photo book or a slide show is to be produced. This is where a special feature of albums comes into play, namely the ability to set the order of the images (Requires full version). Also, an album can be marked as the "current album" and images can be added by simply pressing a key .
Keywords can be easily assigned or removed using the checkboxes in the keyword view.
Keywords are used best to mark the people, places or objects shown in a certain image.
Since the AND or OR combination can be easily set via the switch in the header of the keyword panel, it is possible to pick out all the images that have all the selected keywords assigned to them.
In the interface, the albums and the timeline share the same panel. Therefore, in the albums view, for example, a trip can be selected ("Trip to USA 2019") then switched to the timeline, and there the trip can be searched in day segments. Since the panel of keywords is still visible, keywords can be added or removed by clicks.
Please note
Unlike albums, keywords can be exported to XMP files (F8). Some programs can read them and even preserve the hierarchy. However, many programs interpret the hierarchy in such a way, that parent entries are assigned to images when child entries are selected. I.e. the parent entry "Plants" would also be assigned if the child entry "Tulip" was assigned. This is not the case in fotoARRAY, where parent entries can be assigned to images at will, but do not have to be. A parent entry can also be changed to a normal entry and back. It is also possible to assign child and parent entries to other parent entries, i.e. to move them.