Esp the "bleachbit" searches, afaik bleachbit isn't just deleting an email. It is retroactively scrubbing the logs of the email server (MS Exchange) removing all trace of the email even being processed. Also does it cleanly so it doesnt appear that the logs have been tampered with.
Bleachbit is quite a specialist thing, nothing a normal user would use or have any idea what it actually does. More of a sys admin level of tool.