Oh, I don't know. Maybe to replace a Volvo/TRW power steering pump controller because nobody like you has a clue of the protocol, despite your massive database?
So, that hardware needs to be prototyped somehow. You know..."the easy part" 😂 (which is why you do software, cuz hardware is just too easy). Nothing worse than debugging stuff you shouldn't have to, which is one reason Arduino and Pi make sense.
If you're reckless or experienced, you don't necessarily need to breadboard, as here, or you can use a breadboard shield, sure.
This is out there...it may be useful to someone, which is why I posted it. I'm not going to defend its existence.
Whether I need it or not...not now, but it's there if I ever need it which is the point here - awareness vs reinventing the wheel cuz there are bigger fish to fry an development risks better placed elsewhere.
But yes, as the sniffer you've closed-mindedly taken this to be, you taking a pass on it is the right move.