Only 3 NVMe SSDs and no room for HDD, so do they have dedicated storage cluster via iSCSI-like things, or they don't need HDD? Also I noticed the SSDs must be

Only 3 NVMe SSDs and no room for HDD, so do they have dedicated storage cluster via iSCSI-like things, or they don't need HDD? Also I noticed the SSDs must be changed by open top lid. Curious about anti-intrusion design. Do they choose this design because they (may?) sharing datacenter or even sharing rack?