I just had a thought... The limitation of CF cards is write/erase... What about read cycles? Does that affect the lifespan of a CF card? And, does any writing actually occur on the Workbench partition/drive during the boot process? Would Workbench come up if the drive was write-protected?
I've used one of these in my A4K before and saw a nice drop in boot time as a result. I took it out because it didn't like having a slave device on the IDE channel. But it wouldn't be so bad using SCSI hard drives for apps and such, and simply booting from a CF card on the IDE channel.