With BCC, the mail server still delivers one message to everyone, and tracking cannot tell who opened it. Separate copies solve both problems: each recipient sees only their own address, and opens, clicks and replies are recorded per person.
Sending from the dashboard is available on every plan. Campaigns are in every plan, for up to 50 recipients at a time on Free and 500 on Pro and Business. Every copy ends with a “Do not send me messages” line. The text is the same for everyone, apart from fields for the recipient’s name and company.