Comparison to EasyTAG?

The use cases for the two tools is quite different.

EasyTAG is a tool for manually editing metadata tags in audio files.

Picard is a tool for matching music files to releases and tracks in the musicbrainz database, then filling in or updating the tags automatically (with options to manipulate the data via plugins or scripts, if the musicbrainz standard style is not to your taste).

You *can* manually edit tags in Picard, but the intent is that you instead add missing releases or make corrections on the musicbrainz website before using the automatic features in Picard.