I don't agree. Even if an automated translation isn't using the new language in a "proper"/idiomatic way this can still be a good base to start working, while

I don't agree. Even if an automated translation isn't using the new language in a "proper"/idiomatic way this can still be a good base to start working, while ensuring compatibility. From there one cna start and extract pieces and rewrite individual pieces and do lots of refactoring. It is a long and tidious process, but a process which has a chance of leading to less bugs than a rewrite from scratch, by working on smaller pieces which can be verified one at a time, even if no proper test suite exists.