Sanskrit grammar is complicated enough for basic knowledge of the cases and the tenses/aspects/moods to be less useful than one would otherwise assume. You have sati-saptami prayogas, krdantas are often uses as adjectives while basic text books talk about them in limited contexts. It is a huge mess.
Take this story (https://www.adhyeta.org.in/sa/k/samskrita-chandamama/198404/...). Assume you have a gloss available for some words. Do you really need to know the pratyayas for the nouns and verbs for you to be able to understand the story?