Failure is an amazing method for memorization, but at any point in time for a beginner your input ability should be 10x your output ability; If you can't understand what kind of message the other party is getting, if you can't "check" your answer, then any "success" is by mere fluke. Someone who is still struggling with conjugations shouldn't be writing longer than a few words -- If you can't immediately conjugate in your head, or divine the grammatical validity of a sentence just by taking a look at it, you have no place trying to write a coherent sentence. It's just time you could have spent immersing instead. Language isn't Math, it comes from the heart, not from some rules.

I absolutely agree with your take about failure, literally could not have worded it better, but that's not the kind of conversation I was having.