Andy Leonard has a long and useful post on collecting ETL metrics in SQL Server 2016:
“In an age of the SSIS Catalog, why would one ever employ this kind of metadata collection, Andy?” That’s a fair question. The SSIS Catalog is an awesome data integration execution, logging, and externalization engine. There are a handful of use cases, though, where enterprises may opt to continue to execute SSIS packages from the file system or the MSDB database. Perhaps the biggest reason to do so is that’s the way the enterprise is currently executing SSIS. When SSDT-BI converts pre-Catalog-era (2005, 2008, 2008 R2) SSIS packages to current, it imports these packages in a “Package Deployment Model” SSIS Project. This allows developers to upgrade the version of their SSIS project to SSIS 2016 (and enjoy many benefits for so doing) while continuing to execute SSIS packages in the file system. Kudos to the Microsoft SSIS Development Team for this backwards compatibility!
Andy asks the question I wanted to ask and gives a good answer.