Why does the diskutil shows I have two local hard drives?
If you run diskutil corestorage list, you will get a more detailed list:

CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group 62933502-BEAA-43E6-BDFD-D061365F059D
    =========================================================
    Name:         Macintosh HD
    Status:       Online
    Size:         222140432384 B (222.1 GB)
    Free Space:   0 B (0 B)
    |
    +-&lt; Physical Volume F96E64AE-1ADD-46C6-A64B-2578D6DFE536
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     222140432384 B (222.1 GB)
    |
    +-&gt; Logical Volume Family 0BAEBD36-8C41-4D0F-A66B-1203DAD5649F
        ----------------------------------------------------------
        Encryption Type:         AES-XTS
        Encryption Status:       Unlocked
        Conversion Status:       Complete
        High Level Queries:      Fully Secure
        |                        Passphrase Required
        |                        Accepts New Users
        |                        Has Visible Users
        |                        Has Volume Key
        |
        +-&gt; Logical Volume B719B24B-31B2-4890-BE9F-5BD924723237
            ---------------------------------------------------
            Disk:                  disk1
            Status:                Online
            Size (Total):          221803835392 B (221.8 GB)
            Revertible:            No
            Revert Status:         Reboot required
            LV Name:               Macintosh HD
            Volume Name:           Macintosh HD
            Content Hint:          Apple_HFS


There’s a Physical Volume (disk0s2) and a Logical Volume (disk1).

This sheet explains the situation quite well:


As you can see, you need a Logical Volume; a Physical isn’t enough.