While temp tables are a good option for in-flight data transformation, there are some unique challenges that arise when using temp tables in SSIS.
SQL Server Integration Services uses tight metadata binding for data flow operations. This means that when you connect to a relational database, flat file, or other structure in an SSIS data flow, the SSIS design-time and runtime tools will check those data connections to validate that they exist and that the metadata has not changed. This tight binding is by design, to avoid potential runtime issues arising from unexpected changes to the source or destination metadata.
Because of this metadata validation process, temp tables present a challenge to the SSIS data flow. Since temp tables exist only for the duration of the session(s) using them, it is likely that one of these tables created in a previous step in an SSIS package may not be present when validation needs to occur. During the design of the package (or even worse, when you execute the deployed package in a scheduled process), you could find yourself staring at an “object not found” error message.
It’s good to have alternatives, though there are times when you really just need a temp table.