smartctl & device type mismatch

I will keep it short, I am trying to better understand the different standards of storage type interfaces, but the output of smartctl is confusing me a little. Is this an actual problem in my system (like a saw on another post where some firmware was outdated) or am I misunderstanding the output of smartctl. Observe:

> sudo smartctl --scan
/dev/sda -d scsi # /dev/sda, SCSI device
/dev/nvme0 -d nvme # /dev/nvme0, NVMe device

I have an HDD and an NVMe, but the HDD isn't SCSI as far as I know, unless it is "[Why do my SATA devices show up under /proc/scsi/scsi?](https://unix.stackexchange.com/questions/3901/why-do-my-sata-devices-show-up-under-proc-scsi-scsi) ". But if it is, why can I use both -d ata and -d scsi to get information on it:

> sudo smartctl -d ata --info /dev/sda
smartctl 7.4 2023-08-01 r5530 [x86_64-linux-6.10.5] (local build)
Copyright (C) 2002-23, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Western Digital Scorpio Black (AF)
Device Model:     WDC WD5000BPKT-75PK4T0
Serial Number:    WD-WX11EC114329
LU WWN Device Id: 5 0014ee 6ad29b3f3
Firmware Version: 01.01A01
User Capacity:    500,107,862,016 bytes [500 GB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Device is:        In smartctl database 7.3/5387
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 2.6, 3.0 Gb/s
Local Time is:    Thu Aug 29 14:09:19 2024 WEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

> sudo smartctl -d scsi --info /dev/sda
smartctl 7.4 2023-08-01 r5530 [x86_64-linux-6.10.5] (local build)
Copyright (C) 2002-23, Bruce Allen, Christian Franke, www.smartmontools.org

User Capacity:        500,107,862,016 bytes [500 GB]
Logical block size:   512 bytes
Physical block size:  4096 bytes
LU is fully provisioned
Rotation Rate:        7200 rpm
Logical Unit id:      0x50014ee6ad29b3f3
Serial number:        WD-WX11EC114329
Device type:          disk
Local Time is:        Thu Aug 29 14:09:35 2024 WEST
SMART support is:     Unavailable - device lacks SMART capability.

According to the output of both, ata is clearly the "correct" type, but sudo smartctl -d ata --scan returns nothing, (unlike sudo smartctl -d scsi --scan). Why does it seem that I can use both ata and scsi to access information, and why is it detected as scsi by --scan?