The problem is that app vendors will no longer be forced to use it. That seriously hurts my sense of security as a user of the platform - the very thing why I chose it.
But it doesn't affect Apple's 1P app store, app review process, or other security processes at all, so if you are content exclusively using Apple's App Store then there's no impact. If you look at the Android ecosystem, there have been all kinds of app stores for years. Some run by hardware OEMs, some open source (FDroid), and some that are run by app review sites that basically function as sideloading hubs for pre-GA versions of apps. Arguably, things generally work and overall I don't believe system security has been negatively affected.
The real issues here are with the payment processing captured by Apple & Google, and why their gatekeeping (net negative to competition) should be a profit center for them while at the same time being a net negative (arguable) to consumers.
The real issues here are with the payment processing captured by Apple & Google, and why their gatekeeping (net negative to competition) should be a profit center for them while at the same time being a net negative (arguable) to consumers.