What you say is true but that wasn't my question. Sorry if I wasn't clear.
Let me give a scenario.

I send a message to a business contact regarding an account they he does not
belong to. I want that email message linked to the account. I know it won't
be automatic because how can it be? But, the actions menu does not provide
me with the ability to link before I send the message. This ability only
appears once the message has actually been sent. I have to open the message
again to link it accordingly.

I'm sure this isn't the only case. How many people exchange email with team
members or managers regarding accounts where the accounts are not copied on
the messages?