Sending a poor sequence by hand is self-limiting. It reaches a dozen people a week, somebody reads the replies, and it stops. The same sequence on a timer reaches everyone who ever signs up, at whatever hour their time zone lands on, while somebody keeps paying for the account, and nothing in the arrangement ever prompts a human being to read it again. That is the risk, and it is not only a risk of irritating people. Contacts written to without good reason stop opening anything, mailbox providers treat that silence as a verdict, and the messages you need delivered, the receipt and the answer to a real question, get filed downward alongside the rest. So automation concentrates whatever judgement was fed into it. Built on a correct guess about why people handed over an address, it compounds pleasantly for years. Built on a wrong one, the wrong guess is restated on day one, day three and day seven to an audience that grows every week, in wording nobody has looked at since the quarter it was drafted. The hard part of all this has no interface. Somebody must decide what a person needs to know at each step, what they were anxious about at the moment they signed up, and when saying nothing is better than saying something. Vendors demo the builder because the builder demos well.
The builder is not the decision
Draft the sequence before you build it
One line per message in a plain document, before anything is dragged onto a canvas: what the contact did to set it off, what they already know by then, the single next thing you want from them, and why this message is better than silence. Any line you cannot complete marks a message to delete, and an honest first draft normally loses several messages that way. Record the date each message was written, and reread the sequence end to end once a quarter, aloud if you can bear it, because automated copy is the only writing in a business that is never proofread after launch. The document is also the durable asset. Workflows do not travel between platforms and the rebuild everyone dreads is nearly painless when the decisions live somewhere other than a vendor's canvas. Put a name against each sequence as its owner, because an automation nobody owns is how a company ends up writing to customers about a product it withdrew two years ago. Then build the smallest version that stands up, and add a branch only when something you have read in a reply tells you the current version is too crude.