We're no longer talking about the subject matter, but there is absolutely value in knowing whether an opinion is informed by expertise or not. I did not "appeal to expertise", I merely signalled that I had expertise in the field. This has value.

I suspect that a small minority of Hacker News participants are biochemists/biologists/life scientists, so the default assumption when you read comments on these topics is that they probably come from smart non-experts. By adding this extra information, I wasn't making my argument any better: I was only providing the readers with extra meta-information.

I won't bother explaining the dangers of the appeal to authority, because I am persuaded that you are already familiar with the fallacy. However, I will say that not every form of "expertise signalling" is an appeal to authority, and it is usually a very good idea to defer to expertise.

I recommend this article on the subject, if you're interested in seeing where I'm coming from: https://thelogicofscience.com/2015/03/20/the-rules-of-logic-...

Edit: and I will happily and readily admit that I am not the "most expert" person on any subject, and I myself pretty much always defer to the expertise of those who are more expert than me.