I can't think of any real honest business case where taking backups outside of native SQL is necessary. I hate it when people choose to show the coolness of powershell by showing the most bloated method for backing up DBs on the planet. What DBA in their right mind would choose to take backups and put them in the windows scheduler? You don't get history and it's harder to tell when the job is running and get stats on it.

If you have to run backups in powershell (again, WHY?), then at least call the script from an agent job so you can at least get some history and other job stats.

This is a case of using powershell just because you want to use it, and not because it's the best tool for the job.