Seems like a great way to play through pre-written stories.
Not such a good way to resolve situations that have unknown outcomes.
Yes SD&D is oriented toward playing through the hundreds (thousands?) of D&D modules which have been written. Which is pretty fun.
But whatever official D&D charts and tables are used to run on-the-fly sandboxy D&D (e.g. random NPC generators, wandering monsters, random dungeon creation, worldbuilding tables, etc.) would be a part of SD&D too.