Hi Divya,
the patterns in «Reactive Design Patterns» cover many aspects and difficulties that arise in the context of designing and implementing distributed systems. Within this context, each pattern is applicable to some classes of use-cases as described in the book, so following its advice should not have generic downsides. But if your problem does not require distribution—if running it on one computer without data replication is fine—then you won’t need the patterns described here. It would be disadvantageous to distribute a problem without need, because distribution adds some hard challenges, as discussed throughout the book.
Regards,
Roland
