Thanks for the heads up. I must have been living in a closet as I didn't know this existed. And we're going live this w/e with 2018.3.2, so maybe I will throw this one in here for the mix (at least the enable via TSM). Back to your question, I'm not sure on the applicability, I guess it can make things more flexible especially for "Tableau Online", but I'll have to check with our business users whether this would actually help them or not. I think having alerts generated whenever end users need them is more useful.
P.S. I like the concept of having both fixed schedules and custom user defined schedules, but it seems like one or the other.