I do for many reasons. Personal questions or answers mainly. Sometimes it's because I feel like my opinion may not be well liked and I'm afraid of getting bashed and hated on so I'll go anon for a while and then take it off later if nothing bad happens.
Usually if I have a question that might be sensitive and personal. I really hate that questions asked by anonymous askers rarely get replies. Like within the last year or so I have seen many less answers for my and others anonymous posts.
I never go anon. Used to back when I first became active, mostly because I was a bit shy to disclose details that were sexual in nature in such.
Now, I couldn't care less. It's not like someone will be able to link those sorts of things to myself in person. Sure, it may draw some creeps in but I've gotten much better at dealing with 'em with a quick block and whatnot.
Other than that, I find no reason to hide that it's me behind opinions I leave that may go against the grain or be controversial. I look at it as motivation to make sure that my opinion makes complete sense and is an argument that I can support and back up if it's ever challenged.
If I'm answering really perverted questions and I want to answer honestly I'll anon that shit. People can find you on the internet and you can be fired for things you post publicly. Since my face is attached to my profile I want to be more discreet when I am sharing xrated experiences that may help others. Sometimes I forget to click anon though 🙈I've gone anon for personal questions too.
I'll go anonymous if I get really detailed when asking a question about a personal situation... JUST IN CASE the person mentioned ever finds it somehow and realizes who I am and how I felt (if I wasn't open with them about how I felt).