Bsd-mailx is the traditional simple command-line-mode mail user agent. Even if you don't use it, it may be required by other programs.

The /usr/bin/mail command provided by this package is a very simple one, and does not include many features that can be found in more advanced mail user agents.

For example bsd-mailx DOES NOT support:
- MIME (i.e. no attachments, no UTF-8 or other charsets support);
- SMTP protocol (/usr/sbin/sendmail interface only is used);
- POP3/IMAP (bsd-mailx reads local mailboxes only);
- maildir format (traditional mbox only format is supported).
If the above features are needed, please consider installing another package providing similar /usr/bin/mail interface:
- s-nail package,
- or mailutils package.