I didn't like my post history being available for public access. For example, if I post in a sub for suicide bereavement, that information is meant for that one small community. I don't necessarily want others to be able to see it and know that personal information. The same could go for victim support, mental health, or other health related subs.
I also don't want to be followed. I know there's a way to turn it off but I learned that way late in the game.
the workaround for that is to use different accounts.
I personally am privacy conscious so I used a different reddit account on each device. After I was "stalked" across different subs by one particularly delightful individual after we had a disagreement, I also made it a practice to create a fresh account every 2-3 years or so. I did this consciously on my desktop/laptop, but on my phone it was easier - every time I get a new phone, I make a new account.
The downside is that you lose your karma, which... isn't a downside for me at all.