> I use scheduled SMS all the time.

TiL. I barely use SMS anymore. When I opened my client just now, sure enough, there was a little tooltip by the 'send' button telling me I can hold to schedule. I've never considered a need for scheduling SMS before.

Am I right in concluding this is a new thing? If so, I think it's a bit unfair to castigate slack for lacking a feature that's taken SMS 20+ years to adopt.