Great question! I think Grammarly is a fantastic tool for a first pass. The value of a human proofreader comes from what the AI misses:

Context & Nuance: Grammarly won't catch correctly spelled but wrongly used words (e.g., "affect" vs. "effect", or "form" vs. "from"). A human understands your intended meaning.

Tone & Flow: I can ensure the writing flows naturally and the tone is consistent, something an algorithm struggles with.

False Positives: Grammarly often flags things that are actually correct, which can be confusing. I provide the final, confident "all-clear."

In short, Grammarly checks for algorithmic rules; I check for clarity, professionalism, and human understanding.