To use a language you need "over-learning". It's not enough to be able to recall a word.
You need to be able to recall it very fast, and that only comes through repetition beyond the "I won't ever forget this" stage. SRS doesn't make a statement about this, and you can still use it to achieve that over-learning, in my opinion. It may be better to achieve it through reading texts in the foreign language because the repetitions are faster.
One way you can achieve this using SRS is forcing very short recall times. I average under 2 seconds a card in review: my view is that if I can't recall it in under 2 seconds (what would be realistic in a real-life scenario when speaking a language) then I don't know it. It's a method that's trained me to be very fast at recalling words when needed.
Yeah, it's something I can time myself: I'm on about 6 years of daily usage at this point so it comes very easily. Anki also lets you set a time-out on cards as well. I'll know just from looking at the front of the card whether or not I know the word. If I do, space then 'good'; if I don't, space then 'again'. Very rarely I'll know a card but only after a longer moment to think about it - that's a 'hard' card.
You need to be able to recall it very fast, and that only comes through repetition beyond the "I won't ever forget this" stage. SRS doesn't make a statement about this, and you can still use it to achieve that over-learning, in my opinion. It may be better to achieve it through reading texts in the foreign language because the repetitions are faster.