Ghostwriter also includes 3 features that Copilot does not have: Explain Code (explains code in plain English), Transform Code (translate between langs/refactor code), Generate Code (prompt Ghostwriter to write full programs in one shot)

Plus, Ghostwriter is integrated with the Replit platform, meaning you get all the benefits Replit offers as a portable development environment you can take with you anywhere you go and host instantly.

One could argue Copilot can translate/refactor code.

I can't count the number of times I've copy pasted a chunk, commented it out, then put a comment describing what I'm after. Copilot will get it exactly right ~40% of the time, ~40% of the time it gives me a good starting place, and the other 20% I just scrap.