The thing is, all these arguments can apply to any test you do during an interview. It is always under pressure, and it will always be incomplete. You will never know for sure before you actually hire the candidate.
If the interview for a coding job doesn't involve actual coding, how do you know that the candidate can code? What you may get are people who are just really good at selling themselves. Maybe a good fit for the sales department, but not so much for the technical position you are hiring for.
LeetCode is not perfect, but no test is.
As for the "memorization" aspect. You can certainly memorize solutions. But you can't just memorize every character of every solution and regurgitate it perfectly. You will need to make some generalizations, just to fit everything into your brain, and as you type it back, you will probably misremember something, and have to fix the bug or bridge the gap. Those are useful, real life coding skills.
If the interview for a coding job doesn't involve actual coding, how do you know that the candidate can code? What you may get are people who are just really good at selling themselves. Maybe a good fit for the sales department, but not so much for the technical position you are hiring for.
LeetCode is not perfect, but no test is.
As for the "memorization" aspect. You can certainly memorize solutions. But you can't just memorize every character of every solution and regurgitate it perfectly. You will need to make some generalizations, just to fit everything into your brain, and as you type it back, you will probably misremember something, and have to fix the bug or bridge the gap. Those are useful, real life coding skills.