As per the PBM 1.7.0 release notes, physical backups are still considered "tech preview". However, we're not explicitly stating this anywhere else in the documentation, which may set wrong expectations. Please update the PBM docs and add adequate notices/warnings about this feature still being considered "tech preview", e.g. here:

https://docs.percona.com/percona-backup-mongodb/release-notes/1.7.0.html#release-highlights (in the "important" info box)
https://docs.percona.com/percona-backup-mongodb/backup-types.html#backup-types (in the description of backup types, also a link to https://www.percona.com/blog/physical-backup-support-in-percona-backup-for-mongodb/ should be added here)
https://docs.percona.com/percona-backup-mongodb/running.html#starting-a-backup (in the paragraph that explains what a physical backup does)
https://docs.percona.com/percona-backup-mongodb/pbm-commands.html#pbm-backup (in the table that describes the backup types)