Is it really playing DnD?
Yes, it is really playing DnD.
The experience is totally washed out, where's the face to face interaction with the DM? Other players?
Well, there isn't any. I have met 'a few' of the players in person, and I've known quite a few on a personal level, but there isn't any face to face interaction. All of the interaction is done through words and letters.
What's good about it?
Time, for one. A DM can mush over an idea for as long as necessary to make the best possible decision. Players that don't have more than a few minutes can still get in their moves, even if they couldn't regularly have a face-to-face game. Secondly, quality. Role-playing is incredibly more in-depth in my experience. I recognize characters more than their players, and I love to write more and more background to email my DMs as the game continues. In a face to face game, it's still an option, but it's very 'annoying' to find players that need to make a 20 minute long speach before their next action. This abbreviates that kind of problem.
Also, in PBP a DM doesn't need to know 'too much' before the adventure starts. New ideas are always easy to fill gaps with, and games are problem-free in that respect. It's easier to pump out many different ideas.
Are people just shy? Antisocial?
I'm not either, but maybe some are. I wouldn't discredit those who are. They might have very good reasons.
Agree? Am I insane or just old?
I disagree with you, but completely and totally understand and believe highly of why you have your opinions. I just think that my perspective is different, because I gain a lot of being able to game in-between classes with a few really great people.
Some extra information you didn't ask for...
Well, I must say that this is really crucial to understanding PbP gaming: Combat is slowed down since players are not going to post immediately when their actions come up. This is only slightly resolved by having all players post within a certain deadline (or the DM assumes an action), and resolving multiple consecutive combat rounds. Once you are over this problem, you must also consider the problem that earning experience may be too slow in PbP for players to really feel that they are keeping up with their own character development.
That's right, for the first time in my gaming life, I have trouble getting enough experience to make up for all the hours I spend creating and really getting to the heart of my character. This can be adjusted for by altering the xp chart slightly, and using 75% or 50% experience requirements for leveling... though some people don't feel that this is 'hardy' enough for themselves and stay away.
And Thirdly, miscommunication. My english isn't your english isn't her english, isn't his english. Nobody ever has exactly your interpretation of your words, and you cannot emphasize things with the exception of

. They sure do look nice, but they don't quite carry enough weight like tone of voice does.
Lastly, if the people you really want to game with were there for you at every possible opportunity, nobody would ever play PbP, but that's not exactly a given statement. We all love the game, and I personally can't find a DM that I find credible enough to play with in my region, so I try to get as much experience playing in between my DMing to make the game as fun as possible on both sides.