(Or: Keeping all writings in SRS can give you a "graveyard of notes".)
A surprising fact about SRS: flashcards are not permanent! In the end, every card will effectively disappear from your life because the review delay grows to decades.
It's supposed to be fine because the idea is that at this point, you remember the answer anyway.
I submit that you actually don't remember it in everyday life – only when you enter those specific situations that trigger this memory – which may be almost never. It's not that you remember, it's that you can remember.
And thinking about it, encoding an idea in a flashcard gives you very few entry-points to revisiting that idea so you can develop on it.
Isn't it sad to have put in so much effort crafting that perfect phrasing, and you never see it again?
To put my thesis another way: when I used Anki in the past, I ended up with a habit of actually looking up the Anki database for something I wrote in the past – facts, figures, a good turn of phrase etc. I was accessing it almost like a slipbox!
But Anki is not really made for such browsing, and you can't hyperlink directly to other cards, and it deals with flashcards as its atomic unit: you get to make one card front and center, onto which you can hang supplemental information (as extra fields), whereas I'd prefer it the other way around, because the same supplemental information could be relevant to multiple cards at once.
In a slipbox with integrated flashcards, you can do this! (My solution: github.com/meedstrom/inline-anki)