Yah… the second part of your statement is more interesting than the first. Since SmartThings does not have a public bug/feature request list (and no Community-curated one), then it is hard to say exactly what parts of the system have the most problems, and which of these problem areas are most easily forgiven by Customers … and which areas are critical to Customers.
Regarding the latter: SmartThings would like the consider SHM to be a “core value proposition” for the product and therefore have it lend itself organically to monthly recurring premium add-ons.
There have been many discussions on what SmartThings’s future revenue streams are, paths to sustainable profitability, and so on; SHM add-ons may be among the first paid services, but that doesn’t mean it is the most important overall for sustainable profit.
Convolution? Yah… I guess this is just a very roundabout way of saying that for $99 one time cost, Customers are willing to tolerate some bugs and unreliability; but clearly if a specific feature has additional cost (especially non-trivial recurring costs!), then that area will be subject to extra scrutiny. Would you pay $10/month for a “reliable scheduler feature”? Or $10/month for an “client app that doesn’t have red-band errors and crashes”?