On one side, someone intimidates you into spending a few hundred dollars by telling "insurance will not honor your claim if your house is blown up because of a gas pipe not installed by a "licensed" professionals, although I myself saw a funny professional trying to use sealer designed for sealing water instead of pressured natural gas. That "professional" was kicked out of my house immediately.
On the other side, natural gas does have some possibility of leaking, filling up your house, and with a teeny tiny spark, your house is gone.
All in all, on average, a professional should be more reliable than an average guy, but that is just a typical sample of "probability".
For me, I installed the natural gas pipe by myself. Not because I'd like to save a few hundred bucks, but because that "professional" was kicked out of my premise.
My bottom line is, if you ask me:
1. Can I install the thing myself? Can it be as safe?
Yes and Yes
2. Can you please install the pipe for me?
No, I won't do that. I won't take the responsibility and would like to sleep well during night.