I can’t reveal too many internal details but this data lived in the RDBMS for years. Its access patterns are well understood. That’s exactly when you start cost optimizing. If this didn’t work out we’d just move back to the old DB schema that we were already using and pay for a bigger server. If we wanted, we could keep the schema as-is and just move it into SQL Server. That would work just fine, too. No re-engineering required.

Don’t know how else to say “we were not born yesterday; we thought of that” politely here. This definitely isn’t something to have your junior devs work on, nor is it appropriate for most DB usage, but that’s different than it not having any use. It’s a relatively straightforward solution to a niche problem.