Where manual wins
A real reply is better than an automated one. It is specific, it answers the actual question, and people can tell.
For a small number of high-value conversations — a serious enquiry, a potential client, a complaint — manual is not just better, it is the only sensible option.
Manual replies also teach you things. Reading what people actually ask shapes your next post in a way a send count never will.
Where manual fails
Coverage. When a post takes off you answer the first fifty comments and none of the next fifteen hundred, and the people you missed do not know they were missed — they just did not get a reply.
Speed. Interest decays quickly after someone comments. A reply the next morning reaches a person who has moved on.
Consistency. The fiftieth reply you type at midnight is not as good as the first, and neither is your mood.
Availability. Posts peak at unpredictable hours, and you are not always awake for them.
What automation actually costs
It cannot answer an unanticipated question. An automation delivers what you decided in advance; anything outside that still needs you.
It can read as generic if you let it. One message repeated forever is worse than a slow human reply, which is why variants matter.
It removes you from the loop. If you never read the comments, you lose the signal about what your audience is asking for.
The sensible split
Automate the predictable: link requests, price questions, lead magnet delivery, "where do I buy this". These have one correct answer and benefit from arriving instantly.
Handle the rest yourself. The automation sends the first response; the conversation after it is a normal DM thread you can pick up.
Read the logs weekly. That keeps you connected to what people are asking without requiring you to answer each one by hand.