As of now, the REST API doesn't offer all functions of the Webex Clients. For reactions, I had a use case where an integration would auto react on certain messages on behalf of a user. Also, possibly first step for https://ciscocollabcustomer.ideas.aha.io/ideas/WXCUST-I-8094.
This has apparently recently deleted (?), so I post it again. Was https://ciscocollabcustomer.ideas.aha.io/ideas/WXCUST-I-12776.