Duplicate Post has been a great tool in the arsenal for years and years for me.
Sure WP CLI might make it redundant in some situations ... but not everyone likes working from CLI and having a GUI friendly solution which hardly ever fails (still have to see that happen) is very welcome.

Do hope that it all remains as is ... and wonder what Enrico will be doing within the Yoast team.

Either way, best of luck with both the development and this 'development' ;)