Neither Btrfs nor zram-based swap, inhibit hibernation. There is a kernel lockdown policy that inhibits hibernation when UEFI Secure Boot is enabled.

Since the hibernation image is neither encrypted nor signed, it's a potential attack vector to subvert the UEFI Secure Boot mechanism. Because UEFI Secure Boot systems are common (Windows hardware certification requires it exist and be enabled by default), it was decided to, by default, save the space on disk for disk-based swap and use zram-based swap instead.

It is straight forward to create a disk-based partition during installation, and it is configured to support hibernation, while still remaining subject to the lockdown policy.

It's defaulting to btrfs, which is a poor decision. If Fedora is making such poor decisions on basic things like default filesystems, that gives me more than enough influence to chose one way or another.

They were all aboard with Stratis, but here we are, btrfs moving back in.