There are multiple cases where installing a piece of software or a driver results in that software or driver not working afterwards due to the user not realising it needs kernel headers installed too:
These packages generally don't depend on kernel headers, since putting a dependency in the packaging when you don't know what kernel version/flavour it will be running against doesn't make sense.
So we can make the user experience quite a bit better here by having elementary OS come pre-installed with the correct kernel headers for the kernel flavour we ship. The package doesn't do anything on its own, so there's no risk here. It will just take a few extra tens of megabytes of disk space on an installed system.
There are multiple cases where installing a piece of software or a driver results in that software or driver not working afterwards due to the user not realising it needs kernel headers installed too:
VirtualBox - https://github.com/orgs/elementary/discussions/291 Nvidia drivers - https://github.com/elementary/os-patches/issues/155 Broadcom drivers - https://github.com/elementary/appcenter/issues/1603
These packages generally don't depend on kernel headers, since putting a dependency in the packaging when you don't know what kernel version/flavour it will be running against doesn't make sense.
So we can make the user experience quite a bit better here by having elementary OS come pre-installed with the correct kernel headers for the kernel flavour we ship. The package doesn't do anything on its own, so there's no risk here. It will just take a few extra tens of megabytes of disk space on an installed system.