Depends on what you mean by practical. The software and hardware works (for now, until T2s become required). It allows you to build configurations that Apple do

Depends on what you mean by practical. The software and hardware works (for now, until T2s become required). It allows you to build configurations that Apple does not (and probably will not) ever sell. They are not cost effective if you have a way to turn time into money though. I would not recommend it unless you have lax security & availability requirements and genuinely enjoy low level tinkering with the basic functions of your computer.