عند كتابة بريد إلكتروني؟ إيجابيات وسلبيات؟ bcc ما هي دواعي استخدام Why you might use bcc when writing an email? Goods and bads?

It is to hide the "bcc" recipient, but doesn't work for Gmail recipients, i.e.
if a Gmail user is receiving the email he/she will see the "bcc" recipient.

to send the email to the third person all together in the same time same email.

جميع وسائل التقنية الحديثة مفيدة للأعمال في سرعة التواصل وأختصار الوقت والمسافات والتوثيق ونقل الأحداث

Well me i use the bcc in emails when i need to pass a notice, for example: once a year staff who has taken staff loan from the company, need to make a part payment, so i send the email to only those who have staff loans and bcc them, thus no one is aware who has loan with the company as its confidential matter and on the other side, the message is passed on at one go to the concerned staff.

It is good if you need to confirm at a future date that your co-workers have been informed about a project development or directive.
It is bad if you forget to hide the recipients and someone starts unwanted correspondence with one of the recipients.

When you bcc a recipient of a mail, you are hiding that recipient from other recipient of the mail.
The other recipients of the mail would not be aware that the bcc recipient was actually copied in the mail.