You can still do both. Its just all of the grunt work is no longer grunt work, and all the tech debt you've been putting off is no longer an issue, and all of the ideas you've been meaning to try out but don't have the time can suddenly be explored in an afternoon, and so on and so forth.

For new features, by all means code it by hand. Maybe that is best! But a codebase is much more than new features. Invaluable tool.