For me, at least, ZFS is about a lot more than dedup
You can have dedup on Linux with BTRFS. I use it as standard for the NASes which store source code trees and NFS roots. Once you dedup, the difference compared to ext4 is staggering.
ZFS, however, is not just about dedup and there is no Linux fs which offers identical functionality. You need to use multiple components to get the same effect - btrfs, volume manager, etc.