1. Passkeys are device dependent. That means you need to have more devices and be tied to your existing devices. For a lot of people, that means even tighter phone dependence.
2. Even if you don't use a phone to store your passkeys, they promote vendor lock-in, because you need to rely on Apple, Google, or some other cloud-keychain system to store your passkeys.
Tech companies love passkeys, not because it makes your life better, but because it entrenches people further into relying on their systems. People will love passkeys because it appears simple and makes passwords a thing of the past.
But there's a tradeoff: more dependence on advanced technology are major tech corps. Let me ask you this: suppose you want to go phone-free and big-tech company free. Or you lose your phone and computer overseas. If you only use a passkey, then you'll have to grovel back to Apple or Google to log into your fastmail. Tech corps love that.
This is just one step to make people tied to big tech, and so it seems harmless. But it is part of an overall procedure to integrate us so tightly (free Google docs, log in with Google/Apple/X is another of many), so that we can't function on our own any more, or choose any company we like any more.
When someone eventually makes an account and delves into the more niche subreddits, that's the culture that they're expecting and as more do it, it starts to change the culture of the niche subreddits as well.
Ironically the secret to reddit's success was that it was just left alone with very few changes for so long. The front page was already a dumpster fire at that stage, but a dumpster fire mostly contained to the top 20 subreddits. Now that it's more clever about pulling in posts from more niche subreddits that are doing well, or based on geolocation, it pulls people into the subreddits more which accelerates the Eternal September effect.
When senior government officials are spending time & public mindshare/attention on whether a particular font is or is not diverse then you know it is game over.
The details don't matter...this being a topic at all is the news