The announcement was funny because they weren't quite sure what they are going to do in the health space. Sam Altman was asked, and he immediately deferred to Ellison and Masayoshi. Ellison was vague... it seems they know they want to do something with Ellison's massive stash of health data... but they don't quite know what they are building yet.
Providing a turnkey HIPAA-compliant but modern health dataverse would be huge.
The Snowflake-for-health is more about opening EHR data for operational use by providers and facilities.
Versus being locked into respective EHR platforms.
If Oracle provided a compelling data suite (a la MS) within their own cloud ecosystem, they'd have less reason to restrict it at the EHR level (as they'd have lock-in at the platform level), which would help them compete against Epic (who can't pivot to openness in the same way, without risking their primary product).