The grammar and spell check is not an issue, but if you’re using the rewritten alternatives for a sentence it’s definitely a toss up. Granted, it just uses what you’ve written and provides a few different ways to relay the same info, but then again, it does this via AI. So really idk, but I’ve used LanguageTool rewrites on most of my college papers and I haven’t had any issues. In the big picture, it’s nothing close to using an LLM to write a paper.