"What are the advantages of this versus a PATA disk-on-module, a CompactFlash card, or an SD-to-PATA adapter?" I wondered the same thing ... I have thousands

"What are the advantages of this versus a PATA disk-on-module, a CompactFlash card, or an SD-to-PATA adapter?" I wondered the same thing ... I have thousands of days of uptime on various CF->IDE configurations - many of which were critical infrastructure. It's a really elegant solution because CF and IDE are pinout compatible. No logic is required. I set filesystems to be read-only so as not to burn out the CF part and, again, some of these were in service for >10 years and I have much higher confidence in this configuration than any SSD based solution I have ever fielded.