It's a matter of style guys, not of objective qualities that the game gets or not if you do in a way instead of the other.
What's your DM style?
That's the question.
Do you prefer to control the game by your creativity or to treat chaos (a.k.a."dice") like an oracle for you to interpret?
I confess I'm equally attracted by both!
There is this Youtube post in which Frank Mentzer DMs OD&D without any screen and it makes me think exactly what Skyscraper means with "no barrier", but when he rolls he anyway hides the dice with the hand, fascinating:http://www.youtube.com/watch?v=APPxO-SJVK8
So the point to me is that the game is influenced in a way by conscious creativity, in the other by interpretation of the unexpected and impro.
In the first case the DM is in the position of being a safety net in case; in the latter he's not, and to me this fact favors the first approach.
As a player I wouldn't like a game in which nobody ever dies, neither one in which chaos always frustrates the group with "critical endings".
So, as a player, I expect to feel a certain mood and, let me say, it has nothing to do with the DM's approach to dice rather than what he ultimately says and decides.
Let's call them the vertical (dice hidden) and horizontal (dice open) approaches.
The great masters of the game never stopped to roll conceived (I talked days ago with Ernie Gygax and confirmed it about his dad), and without being taken as a silly emulous, I think this means something.
Something strictly related to a certain "spirit of the game".
Probably I will keep roll conceived (funnel excluded).
Even if chaos charms me so much.
This doesn't mean I will save each and every ass in trouble all the time.
This means I will rule the rules and rule the dice.
To me the Judge/DM is above all, even the dice.
And I want my players still feel the magic of the unknown I still want to perceive every time I sit on the other side of the table.
I still trust in the conscious direction of the DM and the mystery of his deeds which I disregard as a player.