I agree with you that it probably could be better specified, but I think his USP is that it comes with his custom made user interface which promises to make set up a breeze and is essentially ready to plug and play right out of the box. While this is no big deal for people with cnc experience or a technical background, it is quite attractive for non technical newbies like me as it makes linuxcnc a realistic option to try out for a relatively low cost which wouldn't be the case otherwise.

I think it is priced to recover development costs upfront, as there will be cheap clones appearing on all the popular far eastern auction sites within a few months if it is released commercially. I can't really fault him for that if it is his business plan.

I have one of the better specified aliexpress motion control boxes on order. It cost £114. If I get hit for taxes and duty, it will cost about the same as this so apart from needing a keyboard, monitor and mouse (which I already have lying spare) the costs are roughly in the same ballpark. It may or maynot perform better than this or the traditional parallel port PC/ Mach 3 solution but it is nice to have a choice that is usable for someone with rudimentary knowledge.