My goal is not to call anyone out as if they are doing something wrong. I want to understand the why as well as the tradeoffs. Thank you for explaining.

I get what you are saying about real life but SN and Reddit aren't real life. You make a good point about things sticking around forever but I would caution you on thinking that deleting in x days protects your content from being on the web forever. Anyone with basic computer skills can preserve what we post on the web. Its not hard to do.

I think this is a useful feature and I can see myself using it for some comments but as I stated in my post if a large number of SN users start doing this it dilutes the value of SN. One of the massively useful things about the Internet and sites like this as well as Reddit are the archival ability. Don't under-estimate that value.

Of course if you choose to delete all your comments in x days for whatever reason that is your prerogative. You don't have to explain why to me. Thanks for explaining some of your rational behind this. It is appreciated.