Delta metadata based min/max statistics, Parquet row groups and min/max in-file, combined with the right combination of bucketing and sorting, allowed us to actually ignore all partitioning and drastically improve performance on PB scale. The metadata can be a very useful way to do indexing/allows you to skip a lot of things.

It's not magic, and you can understand what the _delta_log is doing fairly easily, but I can testify that the performance improvement over partitioning can be achieved.