If they weren’t comfortable with the durability/availability of local SSDs in the cloud, why would they be comfortable with that plus more with their own hardware?
That said, I don’t totally disagree with you that maybe collocating would be worth it. But they were very clear that they like offloading the work of durable storage to GCP. And they found a pretty elegant solution to achieve the best of both worlds.
Also, FWIW, Discord does offload some workloads to their own hardware. (Or so I’m told, I don’t work there but I know people who do)
