You still need an initramfs in the case your bootloader/kernel doesn't support your filesystem; for eg GRUB didn't support LUKS2 and the Linux kernel can't boot LUKS directly without userspace tools to input the passphrase etc.
Your distribution needs an initramfs for that reason; you as a user can just recompile the kernel so that the modules it needs are built-in rather than needing to be loaded separately from a ram-disk. If you need an early-boot file system at all (as with an encrypted /), it can be provided in /boot/ and then "swap root" to / at boot like initrd does.
