Just curious, why would this method be preferable over just creating a SQL Agent job and directly executing the dtsx? I've seen references to uploading SSIS jobs into the database before, but I haven't seen a good discussion on it's benefits vs the alternative.
If the package is part of an SSIS project you can take advantage of project parameters and connection managers; unlike when copying a single .dtsx.
Also, the reporting of a job execution is more robust when the job is run out of ssisdb. It's an SSRS report. The reports have A LOT in there, which can be good or bad IMO 😉