Chemical synthesis is much more than just retrosynthesis. Even if it was, you can not just plug in the novel previously unsynthesized molecule and expect any reasonable results. Furthermore, the tool is based on Reaxys which in turn uses already established reaction routes and conditions from literature and patents. Good luck optimizing yields for something you don't know even how to synthesize, let alone what conditions to use.
> Chemical synthesis is much more than just retrosynthesis.
Of course, but we are talking about chemical discovery - after which you want to test if the compound theoretical capabilities work on cells. Yields are not yet a concern!
> expect any reasonable results
No it won't do all the work, but it will direction, and suggestion for which pathways could be used.