This seems interesting, but I've been using Alpine as a desktop distro wth ZFS for years now, it has native support and ZBM is available in the community repo. Not sure what advantages Chimera would add.
Do you notice any performance advantages on Chimera?
As for system performance, mimalloc's effect isn't particularly noticeable in regular use. Or maybe I just don't stress the allocator often enough. There may be more daemons running by default, but they are also activated on demand if you aren't using them, so YMMV on that.
For desktop use, it feels like an early (but already quite usable) version of what a respectable systemd replacement would look like, and I think that's its greatest strength in practice.
IMO they should be best thought of as research projects useful for reference by distros designed for production use.