A routine product question can usually stay in the Page comments. If someone asks whether an item comes in a particular size, a public answer helps that person and anyone else reading the post. It also gives the team one visible answer to keep consistent if the question comes up again.
Messenger makes more sense when the answer depends on information that should not sit under a public post. An order number, delivery address, or account-specific issue changes the job from answering a product question to handling an individual case. A Page reply can acknowledge the question and explain what detail is needed, then invite the person to send it privately. That leaves a useful public response without asking them to disclose personal information.
Teammate handoff is the other deciding factor. Moving a conversation only helps if the teammate who can resolve it has access to the Page’s messages. Before making Messenger the default route, check Page access and whether the relevant teammate can see the conversation in Meta Business Suite Inbox. Otherwise, the public comment may be visible to the whole team while the private follow-up waits with the wrong person.
For example, “Does this come in blue?” belongs in comments. “Can you check why my blue one has not arrived?” needs a private follow-up, with a brief public acknowledgment.
What rule does your team use to decide when a Page comment should become a Messenger conversation?