I figured, why guess what Dan Heisman would say . . . as I have taken some lessons from him, I emailed him about my own situation. In particular, I told him that the article seemed to imply, but didn't come out and say, that blitz is for over 1400, and my OTB rating is far below that. So I asked him if I should be playing blitz at all? His response:
While blitz games are difficult for beginners, once you get beyond beginner they are certainly possible.
The first issue is whether blitz games are fun; if they are not fun for you, that end’s that. If they are fun, they can be good:
- It’s the best way to practice openings since you can still look up games afterwards and you can play a ton of fast games for every slow game you play
- It helps you practice recognizing safe (or unsafe) moves quickly, and
- It helps with time management since that’s so important in blitz games
So, unless you get addicted (not good), then sure, you can play Blitz games – they can be very good for you 5|5 is a good speed. I have never written anywhere that players should not play blitz games; what I wrote is that if you want to improve you need to play a lot of long time control games (too), and a steady diet of intermediate time controls can get you into bad habits for slow games.
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Yeah, speed chess addiction, I stated that one myself. 
People will often overdo. I almost never play blitz, but for instance, I played blitz for a day on other site a year ago. Afterwards, it took me a few longer games to get my time management in order. If you overdo shorter games, you will rush in your longer games as well.
That is why many people say that you shouldn't play blitz at all. It is not that it will hurt per se, but you can easily play too much for your own good. In any case, longer games are essential, and are most important. A little blitz here and there can be played, and might be a good exercise for your opening play if don't abuse it, but you can do without them as well. It all depends how much you want to play blitz. 
@nklristic -- I'm just curious (from a data-geek perspective), how did you find that game in the archive? (I gave up trying to find stuff in a chess.com archive, and so I started using SCIDvPC to store my live games -- yeah I have to copy them over from here -- and I keep them in two separate files, on for blitz games and one for slow & OTB games. That makes it much much easier to find a game!)
In any event, that's an awesome game! Thanks for sharing.
I think we pretty much agree on everything. That's an interesting point about whether younger folks will avoid 30+ minute games, and for us to not discourage them too much. I wonder what DH would say to such folks.
Nevertheless, if somebody is serious enough to pay a coach -- I'm surprised that the coach is recommending 15 minute games.
As for post-game analysis -- yeah, that's a major time investment, for long games. For blitz games it's easy, because I'm mostly focused only on what's the *first* move I would have done differently? I'm a bit older, think a bit slower, and so my blitz games are blunder-fests for me -- blunders I would never make in a slow game. So once I get to the first big blunder, I stop looking at it.
Luckily, for me, I am within a 1/2 hour of two chess clubs -- one meets on Monday night and one meets on Tuesday nights, so I usually get around 4 OTB games per week. Lots and lots to analyze from those games!
Actually I found it from memory. I remember that I had one really fast Owen defense game around spring last year (to be fair I thought that it was a little earlier than it actually was), but I knew it was not in the first 2 months or so of playing here, because I experimented with 1.c4 for a month last year almost since I started playing. So it wasn't that difficult to find, after 5 minutes or so.
You should be able to find it with explorer and choose My games option instead of master games, but for some reason when I go to explorer, it doesn't show me this game. Perhaps it was too short or something, I am not sure. It shows that I had one more game against this defense (but it doesn't show this shorter game for whatever reason).