I've said before that the perfect road bike suspension would need to be invisible, because none of the wannabe roadies who bought carbon bikes will want to be seen using it...

There's still people arguing that "you don't need suspension on an MTB"...
And for that matter, there's still people riding penny-farthings arguing that "you don't need pneumatic tires..."

Eventually most road bikes will have suspension, for the same reasons that most MTBs come with it now. Comfort sells bikes, and saddle pain is probably the most-common complaint that bike shops hear.

It does have one advantage for touring--in that if the thing breaks, you can just remove it and mount your saddle normally.
And because it's just a simple spring, it would not creak like shock seatposts can.
Some people might like it I suppose. It would help over bumps, but there's several other causes of riding discomfort that it won't affect.

If you want maximum comfort, then you want a recumbent bike. No butt pain, no hand numbness and no neck strain,,, and recumbent riding shorts don't even have padding in them.