Gas pipe compression fitting

I saw this fitting on my gas pipe under the house where the pipe had been modified probably 30 years ago and I didn't like the looks of it. Then I saw one on the shelf at lowe's and realized that is has rubber inside, and that makes me really uncomfortable. Would you replace it with something better or leave it be? I also found (and already removed) a copper gas tube that had a nail driven all the way through it and was repaired with electrical tape. To say there's some shoddy workmanship in this house would be an understatment.

Is this a bad place to ask a gas related question, or is everyone afriad I'll blow up my house and then try to sue you for giving advice?

Working on gas lines is not recommended for DIY. True, many of us do it, most who do get away with it, but a few blow themselves and their homes up. Water leaks are one thing, but gas leaks can ruin your day. I sure don't know about that fitting, but I would really question it. Big Box Stores often are not the best place to seek advice, and just because they sell it, doesn't mean it's OK to use.

Rubber washers are used at the gas meter.

It used to be that unions were not allowed in the middle of a run unless it was a bolt up flange, or reverse thread on side side coupling. Then CSST gas tubing came along, and there are unions all over the place.

Your fitting has been in place 30 years. I'm not so worried about it. It is bizarre lookin though. I haven't installed anything like that. Nor would I now.

Dresser cplgs are approved by National Fuel Gas Code, NFPA 54, are approved for 150#
But that doesn't mean its a quality brand in place,installed correctly, or something I would ever use beyond a temporary repair.