In one sentence: Apparently, the primary objective of the seminar is for students to learn professionally presenting information related to their field.
This presentation involves both an oral and a written part. Among these, it is arguably the oral part where you can commit many more mistakes that the seminar can address. Mistakes in the written part, beside very general stylistic conventions, often depend on individual styleguides, are pure language issues (and thus beyond the scope of university courses - language majors excluded), or depend a lot on individual circumstances thatbmay or may not be the case in a text written by a student. This supports putting more weight on the oral part.
That does not mean that the contents of documents is generally unimportant, just that it is not in the focus of that particular seminar course. Of course, students are still given topics from their field, and there are several reasons for this:
- Presumeably, it is one general topic that can be assumed to be interesting for all students in the seminar (adduming they all have the same major).
- In case there are any peculiarities when presenting information in the given field, these are best conveyed/highlighted/discovered by presenting on-topic information.
- while students may be assigned different concrete topics, referring to the same field makes the talks at least remotely comparable in terms of style of information presentation.
On top of that, your task probably requires even a bit of thinking rather than just gathering existing information - if only to make the task not as dull for you, and maybe also to reduce the probability to find a ready-made solution that exactly fits your particular topic. Still, the task is probably still not highly creative as such (at least I would not consider the development of a totally new technique a suitable topic for such a seminar, or anything else that is not mostly a "routine" task in the respective field). Much of the work you spent was likely spent on tasks such as literature analysis, which should help structure the information for both the written and the oral parts alike.