IDE-SATA adapters are very common (and cheap), but this seems like SCSI-SATA which is definitely far less common; I know there is also SAS, but I'm not sure how that compares. There have been IDE-SCSI adapters made in the past too, but they've also become rare and expensive:
https://duxbridge.wordpress.com/2012/01/15/creating-ssd-for-...
as well as the device being firmware upgradable via USB
My first thought upon reading that was "that seems overly complex". Looking at the rest of the features, this seems more like an embedded system doing the translation rather than a simple (hardware IP) adapter.
SATA at 600MB/sec is plenty fast for contemporary mainstream server applications , which you can scale up with RAID 5/6/10 with some error resilience.
For higher throughput (plus more IOPS generally), SAS RAID comes into play. AI and processing servers generally come with NVMe disk stacks, configured with mdraid / RAID 0 generally, because the data is generally ephemeral, so losing the data is highly unlikely. You restart what you do on an other server, most of the time.
There's probably an FPGA or fast DSP which can handle signal/protocol translation with some state handling coprocessor on board, not unlike a (spinning) disk controller.
As with all technologies though, the cost first starts out high as it's introduced, is reduced as it becomes popular, and climbs back up as it's obsoleted and nobody makes them anymore but some people are stuck using them.
Sounds expensive!
I run this in a couple retro systems and it's great: https://www.scsi2sd.com/index.php?title=SCSI2SD
Serial connections can actually be faster in practice due to syncing problems of parallel (SCSI-like) transfers at speed.
