There's little reason to put Armory's (or bitcoin-qt's) blockchain on SSD or have it encrypted from a cost-benefit point of view.
There's little reason to have unencrypted drives at all, for any application.My laptop is unencrypted because the CPU doesn't support Intel's AES instruction set so I can only pull about 100MB/s encrypt and decrypt, however, I can easily pull 500MB/s throughput without it.
My desktop is unencrypted because I see legitimately no need for it, and, although I would do it if it were easy, configuring dm-crypt over mdadm would take about an extra hour and I'm way to lazy for that.
There you go, there's two reasons. I do own some computers that do have full disk encryption on data drives, but, absolutely none with full disk encryption on the boot drive, way too much hassle and slows disk access down too much, even with perfect configurations.
