The idea to broadcast an electronic program guide along with the actual media data is a very clever idea. The data can be used to provide a minimal TV guide that allows to show what is currently on air for a specific channel in the next hours. The standard also includes additional fields like the duration, a short description and more low-level details like audio or aspect ratio. However, most of the fields are optional and therefore can be empty. That means, we cannot expect more than a list of titles, with the duration and the channel. The rest is up to the service provider.
In case of movies, we would at least like to present a short summary, maybe a certificate and a genre. But it cannot be guaranteed that this information is present and as mentioned earlier, it also depends on the channel. In other words, on one channel, a movie might have a sufficient description, while on a different channel, only very basic information is present. And even worse, if a movie is aired at different times, one record might have full details, while the other one provides only basic fields.
The restriction of details makes it extremely hard to provide an interface that is satisfying for users. For instance, a record that cannot be classified as a movie, because no summary is provided, is very hard to put into context, especially when the title is not the original one. Then, the user is forced to gather more information with external sources, like a media database, a search engine or TV guide website. At the end, the user might not benefit at all from the EPG data since in most cases, external information had to be used to make a decision. In a nutshell, EPG data is extremely useful to get an overview what is on air right now and also for the next days, but depending on the channel, no extra information are provided. So, if you just want to know when your favorite sitcom will be aired, EPG will suffice, but if you want to integrate the data into a real service, for instance a personalized recommender, additional data is required which is a pity since the standard defines those data, but did not declare it mandatory.
To be fair, gathering all those details is a lot of work, but the data could be reused whenever a movie is repeated. Plus, to provide simple genre is often much simpler than to provide a short summary for a movie. And to tag items with very basic categories like “movie”, “series”, “report or “show” is even simpler. Nevertheless, it is a pity that the limited mandatory data defined in the EPG standard makes it often necessary to consult third-data party for a final decision.