It's not really devoid of meaning if you understand the space. Roughly, Salesforce is about processes and Slack is about communication. Think about handling something like responding to a RFP. Salesforce is good at breaking that down into several pieces of work and assigning them to different people, but the communication and UI sucks. Slack makes communicating across a team easy but lacks the tools to build in formal processes. Combining those will, at least theoretically, end up as a better product.