What is genuinely worth having early is short and specific. A message that arrives immediately when somebody fills in your form. A welcome sequence for new subscribers. Reminders before appointments. A follow up after a job asking whether everything is fine and inviting a review. Every one of those runs on tools you probably already pay for, and together they cover most of the value the category promises.
The reason to be cautious about the full platforms is that their value scales with list size and complexity, and their cost and configuration burden do too. A business with three hundred subscribers and one service does not need branching logic, lead scoring, or multi stage nurture flows. Configuring those consumes weeks and produces sequences sent to an audience too small for the sophistication to matter.
There is a failure mode specific to automating early, which is that automation makes it easy to send more while making it harder to notice whether anybody wants it. A business sending four automated messages a week to a small list is producing unsubscribes and complaints faster than it is producing customers, and the metrics look like activity rather than like the problem they are.
The rule that keeps this useful is that automation should replace something you would otherwise do manually and would want to do. If you would not personally send that message to that person at that moment, automating it does not improve it. The test is whether the recipient would recognise it as reasonable if they knew a person had decided to send it.
Build these one at a time and check each after a month, rather than configuring a system. Add the form response, confirm it arrives correctly and that people reply to it. Then the welcome sequence. Then whatever the next repetitive thing is. That sequencing produces working automation, where attempting the whole apparatus at once usually produces something half configured that nobody trusts.
Audit what is currently sending on your behalf every few months, because automated messages outlive the reason they were created. Sequences configured for a service you no longer offer, or referencing prices that have changed, continue running indefinitely without anybody noticing, and the first sign is usually a confused reply from somebody who received one. Listing what is active takes minutes and is rarely done.