We have a requirement to host a storage solution in a datacenter, and since we can't control the security of the facility (it is shared colocation space with only a flimsy rack lock separating the data from an intruder) our customer insists on encrypting the data on disk.
The customer can live with the fact that after a restart a passphrase needs to be entered manually if no other solution exists. We have remote console access, so besides possibly introducing a bit more downtime we can live with this as well.