Its truly adviseable, because there is only one tomcat which is consuming resources for its system operations.
The disadvantages are following:
- Systemchanges on Tomcat system level require both application to stop
- port or network settings have to differ, both applications cannot use same ports
- high resource consumption of one application can slow down the other application, as there is only one ressource pool to use
But Tomcat is designed to handle more applications than one. Ressource consumption is in a cloud environment truly no problem and reducing the memory stamp for the tomcat itself is a good thing.