I agree the Oceanic housing could become quite good if they can fix the software.
I don't think the OP's experience video is representative though, being out-of-date in the meantime, due to multiple software updates. If this case were really so bad, it would be getting bad reviews everywhere, which is not the case. Ahem.
The product came out very recently. Starting w/brand new hardware and software like this, it would be a mistake to expect a completely seamless experience. If you want a seamless experience, don't buy v1.0 of a new product concept like this, right after launch. Complaining is fine – but this is just reality.
Personally, I wouldn't treat the Oceanic case as a full-fledged DC. I don't want my DC to be dependent on terrestrial hardware that must be protected/sealed & unsealed correctly on an ongoing basis. That seems kind of dumb. But I think the DC functionality is still useful, as a potential backup, and as a sort of heads-up display that you see even if you're getting absorbed in your photography.
Too bad there’s not a separate app for the housing than the Apple Watch Ultra with its dive computer focus.
Not quite sure what this means- the AWU is not part of using the case. Unless you're just referring to visible DC info, which I think does have some utility. I wonder if there's an option to turn off all display of DC info.