An LLM would only be able to "polish" a non-native speaker's writing. Otherwise it is not conceivable that it could improve the essential nature of original research being communicated, this is as said original research will not be part of its training dataset.
Scientists who hope that using an LLM to help write a paper will improve the quality of their output are deluding themselves.
> An LLM would only be able to "polish" a non-native speaker's writing.
Are you really suggesting that all native speakers write perfectly and their writing never needs any corrections whatsoever? I consider that far from the truth for any native speaker of any language and I would of never assumed that.
Everyone's writing can be improved. However, for native speakers, and especially if they have the level of education where they are producing original research, it would be a rare case that the writing was so bad that the science being communicated was undecipherable.
Scientists who hope that using an LLM to help write a paper will improve the quality of their output are deluding themselves.