Advantages of using AWS elasticache.
For high performance setup/website where sub-millisecond response time is needed AWS elasticache comes into existence. Such kind of cache is useful for storing data which is very frequent in use and hence every time needed by a website/application. So instead of the application sending the query every time to the respective server (which consumes much data transfer time) the data is stored in elastic cache which is very fast and hence takes less response time.
AWS elasticache can be scaled in & scaled out to meet the respective application demands.