So if a VM dies, oVirt will provide non-FT failover, yes. And by having failover you might achieve HA. And oVirt is a critical part of making that possible. But it itself isn't HA, nor does it guarantee HA. It's just a failover component that you can use to "do" HA.
It's a component you buy (well, this one is opensource, but still), part of a solution that would cover other potential failure points. The solution in general is also something you can buy, in order to achieve a certain level of HA for those VMs