Adding extra non-cast credits suppresses the cast credits in the DVD section. This reduces the effectiveness of the filmography feature in DVDs, a very nice feature of the system (click an actor's name to see his/her film credits in Cinema). Most users would rather know, when browsing in the DVD section, which films star Daniel Craig or Sean Connery rather than who wrote the script, etc.
The system could be redesigned to suppress writer, producer, etc., credits, but it would be easier not to include them since the system is not designed to accommodate them. Full credits are available in IMDb, and there is a hyperlink on most Cinema entries to connect directly to these credits.
In the CD section, imagine suppressing artists such as George Harrison, The Beatles, etc., and instead displaying the name of the cover artist, the record producer, etc. It would be irritating and confusing.
Many DVD entries display no credits at all since the Cinema entry hasn't yet been input. Many DVDs display no credits since they lack the film's exact title so that credits are transferred from Cinema (especially true for collections of films). Some DVDs display credits for a different film than the one shown in the image because the qualifier (often a date) is missing (these can be confusing and somewhat difficult to sort out). Why not work on correcting these problems rather than adding unneeded extras?
As I wrote previously, it would be helpful if participants would input both Cinema AND DVD records in order to learn how these modules are connected.
There was no link here to the DVD because the DVD entry lacked the Cinema title, which I have now added. When clicking on the DVD entry, which now shows, you can see the abbreviated credits.
A better is example is seen on the James Bond movie Skyfall. Take a look at the Cinema entry, then click on the DVD icon, and you will see that not even 'James Bond' Daniel Craig gets a credit on the DVD entry.
I've noticed several additions of lengthy credits to some of my Cinema inputs. However, Cinema records are intended to be stubs of IMDb records, not to replicate the lengthy credits found in IMDb. For this reason, the input screen for Cinema contains just a few lines— in most cases, these few lines are more than enough to create a stub.
While it's possible to add extra credits to Cinema, this should (in my opinion) be used only for rare exceptions. For example, while one participant may want to list all credits for soundtracks by, say Les Baxter, the next participant won't. So adding extra credits leads to additional ambigious search results if one is interested in soundtracks by Les Baxter. (One might also use Lists or Tags instead of extra credits for special interests).
The primary purpose of the Cinema database seems to be to link video content in the DVD section (all available versions of a film are visible from the Cinema entry. The Cinema entry can be viewed by clicking on the Cinema record display on the DVD record).
When extra credits for producer, writer, director, etc., are added to Cinema entries, this reduces the display of credits in the DVD section. So, for some of the recent changes, the acting credits disappear on the DVD record. Thus, when looking at a DVD entry, one can't tell who the stars of the film are. In general, the stars are the primary interest for viewers using the DVD section, not specialized technical roles.
It helps for participants to be inputting records in both the Cinema and DVD sections. Doing so makes one familiar with the links between the two systems, and helps illustrate the 'why' of using brief credits, adding dates to separate identical film titles, including images of film credits and DVD covers to document the order/spelling/importance of credits (especially when changing/correcting these from what appears in IMDb).
It may be helpful to think of the Cinema records as theatre marquees: there are just a few lines available for text. The person who letters the marquee must choose carefully to create a brief, informative display.