2. Teddit rewrites all Reddit URLs to the Teddit host. Reading Reddit via old you'll still be redirected to the standard "new" site if "www.reddit.com" is hardcoded into a link, and it very, very, very frequently is.

3. Teddit's persistence works even if you're not logged in (which is to say: always, as you can't log in via a Teddit instance). Reddit's "just set your profile preference to "old" requires logging in and can lure you into visiting or posting "www.reddit.com" links rather than "old.reddit.com" links.

Cumulative dark patterns on Reddit spurred me to all but entirely abandon the site years ago. I no longer post updates to my own (several) subreddits, nor actively moderate (again several), though with some regrets on that last (a dark pattern itself).

I'll occasionally visit to research something, or post for support for tools which principally use Reddit for support (DuckDuckGo, Firefox, and Onyx, presently). That's ... down to a few times a year.