I don't think so. In the course we are learning which words we can use in which cases and this sentence may teaches us what is the real meaning of "at" with different examples, and sometimes it happens that a word seems unnecessary but also seems logical to use, the goal is to understand in which kind of sentences you could use it :)
In french we use only the sentence with "that" : je vois qu'il mange son repas" litteraly : I see that he is eating his meal. However we should say "je le vois manger son repas" litteraly : I see him eating his meal.
I hope my reply will help, or maybe a Danish man could put a light on us :D
How do you audibly tell the difference between ser and siger? They sound exactly the same to me in the male pronunciation, and either would work in this context, right? I say that he is eating his food. I see that he is eating his food. Without further context, shouldn't either be accepted? Am I missing something?
"Siger" is either said "see-yi-or" or "si'r" cutting out the middle "yi" sound. But in both of them the "i" is the elongated "ee" sound. In "Ser" the sound of the "e" is flatter and shorter. But even though they to the relatively untrained ear can sound somewhat similar, they aren't, and they definitely shouldn't be treated as interchangeable in sound exercises.