Very good points. I follow the same rules, because I often like to take the controversial or unpopular side to find out whether people are arguing based on reason or 'talking their books' (as they say in finance). That got me into hot water many times. My earliest education about crowd behavior in internet groups came in 1993, and since then I do not feel comfortable about using my name or picture or anything personal.
Biostar is a very focused community with specific Q&A format, providing less room for arguments. However, my experience with academics had not been very positive. Academics are very closed-minded, if you challenge any of their cherished ideas. Software groups are usually better, but I found the professional pessimist communities among the most open-minded about new ideas.
I will just answer on the first paragraph: I did not put my photo picture 2 years ago because I was novice in the field and did not feel comfortable with putting it next to the questions that might be too trivial for the community. And beside, I love what transposable elements did to corn at my picture!!
I honestly didn't really think about it. It's kind of my default behavior on sites like this.
I guess looking back on it, it might be useful at conferences if you recognize people you "know" from the internet.