Once you have a report that everyone depends on, you're not going to want to refresh it manually each day. The Power BI service has the ability to refresh your datasets up to every half an hour for the Power BI pro edition when you're not doing real-time analysis. If all of your data lives in the cloud, refreshing is very simple. However, if you have some data or files on premise, you must install the on-premises gateway.
Don't forget that if you want to see data in real time, you have the option to perform a direct query, where clicks run queries against your source system. Doing this will slow your reports down by large factors. You can also do real-time analysis of your data by using Azure services, such as Stream Analytics, where elements in your dashboards refresh every second.
The on-premises gateways can be used across multiple...
