Here's another of my “opinions”/observations.
Apple could have made the Apple Health app part of iPads/iPadOS years, ago, when the Apple Watch first came on the scene.
So, why didn't Apple make the Health app ever available to iPads after that time? Only Apple knows.
Heck, Apple still has no native calculator app for iPad after 12 years of iPads and iOS/iPadOS versions.
Apple has since kept this glaring app omission as a very low priority on their list/s of thngs to do.
Especially, given the fact, that there is a whole entire third party “cottage industry” of calculator apps for iPad/iPadOS for, at least, the past 8 years, or so.
You can thank the third party developers of the Dark Sky weather app for Apple, finally, getting a native iPad/iPadOS weather app.
If no third party weather app had interest Apple enough to purchase and further develop and use, the iPad/iPadOS would have, still, no native weather app, either.
So, why Apple does what it does, when things seemingly do not make much sense? Again, only Apple knows and they can keep their company activities pretty secret when they need/want to.
Something to think about.
Apple's largest users are iPhone users and Apple seems to think/believe that their larger base of iPhone users don't want the Health app on iPads/iPadOS.
Maybe because of not enough iPad user feedback on this issue ( in all the years that the Health app has existed ) for Apple to make the efforts to push the Health app to the iPad/iPadOS?
No way to know that, either.
The Apple Watch still cannot be used/paired with an iPad, after nearly 6 years!
Why? Only Apple knows, but I suspect it is linked to continuing iPhone sales and NOT iPad sales.
The reason my wife and I never owned an Apple watch until we both switched to iPhones/larger screen iPhones.
Lots of things that Apple seem to not want to do for only reasons Apple only knows.