Stackup provides some advantages over using awscli or aws-sdk directly:
It treats stack changes as synchronous, streaming stack events until the stack reaches a stable state.
A Stack#up facade for create/update frees you from having to know whether your stack already exists or not.
Changes are (mostly) idempotent: "no-op" operations - e.g. deleting a stack that doesn't exist, or updating without a template change - are handled gracefully (i.e. without error).