I think its worth thinking where certain properties come from. A comfortable steel bike will be comfortable because of the compliance of the frame. Most race bikes are built to be stiff. Now compliance is the inverse of stiffness, so you can only get one or the other. But what if you want a stiff and comfortable bike? You can do what most builders do (or try to do) which is build stiffness in places where stiffness is needed most (bottom bracket, for example) and compliance where compliance is needed most. Decoupling two of the contact points is, in my opinion, an elegant way of dealing with the challenge of having both stiffness and comfort. Your bicycle can still be as stiff as it needs to be, but the rider will have some of the road feedback dampened out, leading to a 'smoother' ride. Whether Trek's solution works or not I have no clue as I have never ridden a Domane (nor do I think I will have a chance to do so any time soon) but, at least in principle, I find the idea of decoupling seatpost and handlebar* to be clever, maybe even 'innovative.'

Decoupling btw is what, for example, those saddles with small springs on them do. Incidentally, it is also what we do when rising our butt from the saddle when riding over particularly rough terrain and similarly why a light grip is far less taxing on the body than a very tight grip on the bars.