I think the apples-to-apples question would be "what's better about this vs. Terraform modules", which is IME the most common approach to composition of infrastructure-as-code right now.

Terraform modules are definitely a bit rough in places, for example having to define `variables` and `outputs` at each layer of composition.

But on the flip-side, spelunking into TF modules is really easy when you want to figure out what's going on (I can usually make sense of the module from reading the Git repo), and I've found the Pulumi intermediate representation to be significantly harder to grok (especially if you're pointing Pulumi at a Terraform module that they have translated to TypeScript...)