Monica is closer to a text toolbar you summon on selected text. ReplyPilot is closer to a command inside a supported comment box. Our compare page says to choose the entry point you'll actually use, and that Monica has a stronger case when editing is the daily job.
A precise instruction beats a tone label either way. "Ask one question about their onboarding metric, no pitch" works better than "make it friendly".
Read the policy for the product you're installing. Privacy and subscription value only make sense against the workflow you keep.