You can check or review detailed statistics of a specific marketing email in a customer journey record.
(if you customer journey target is Account, it'll send marketing email to all contacts under account)
For example, you can check statistics of marketing email A in customer journey A.


It can be said that it won't generate entity records in Dynamics 365 Marketing application like activity email,
but once an email had been sent to contacts successfully, it'll still generate insights records as confirmation that the email had been sent to target contacts.
In this example, 3 emails has been sent, so there are 3 insights records.

In other word, sent marketing email records couldn't be reviewed or checked by us directly, but we can take insights data as confirmation indirectly.
Regards,
Clofly