And even the argument of “iPhone users spend more money and are more valuable to developers“ misses the point: these are supposed to be deployed on things in the real world, you want any person who sees it to be able to use/buy it.
To the extent that all of the app clip functionality seems to work equally well via QR code, using an Apple proprietary code really only adds friction to android users, it doesn’t decrease friction to iOS users. There’s no reason to use it that I can see. Of course it’s still early days, maybe Apple has some trick up its sleeve we haven’t seen yet.
It really depends on your market. If you're a parking garage in the US, about 60% of your customers are using iPhones (assuming your customer base is a perfect sample of the US at large, which is also not true). I can only think of a handful of instances in which a business type in the US would have a majority of Android users.
You can find Google's introduction video here: https://developer.android.com/topic/google-play-instant
Just by comparing introduction videos you will see how their visions are different about this feature.
And Apple is going to push for those use-cases. And the good news is that Android has a similar feature. So it makes it easier to justify the effort and investment for companies to build that for users.
It's not like it's a big secret they are trying to hold or a fraud they are perpetuating. Why is there anything wrong with not advertising it?