I’m really surprised you can’t enroll a contact into a sequence via workflow.
I was fully expecting that this would be possible and was shocked not to find it as an action. The workflow and sequence functionality is one of the main reasons I purchased.
From a productivity point of view, it would make no sense to have salespeople process each lead that comes in via a form to put them in a sequence. Also with the knowledge that fast responses make sales, everyone obviously wants very quick responses which would be delayed by manual sequence processing. You want that incoming form submission to get an immediate email.
Please add this ASAP. This is a serious limitation.