Why Should I not connect to the Same iSCSI target with multiple initiators?

iSCSI gives you block level access to the storage pool, which you then put your own filesystem over. Most filesystems are not designed for concurrent block level access and will quickly degrade causing a loss of data.

If you happen to be using a filesystem designed for concurrent block level access, then by all means attach more than one initiator to the target in whatever manner is allowed by that file system.