Old.reddit UI fills the entire width of the screen, and default view is compact. You see more of the feed at a glance without having to scroll as often. When it comes to comments more of it is displayed when it comes to nested comments before clicking.

New reddit takes up a lot of space. And clutters up the side with stuff like related posts when you check the comment section.

Another big one is reddit enhancement suite which lets you tag and block things only works on old.reddit.

Before phones and mobile apps became the norm, people browsed reddit on a desktop browser, and old.reddit is formatted to work with that type of view. No-frills, more efficient use of screen real estate, and everything is easy to reach. It’s the people who used reddit when it was like that who are loyal to it.

Nowadays, most reddit users probably don’t even know that it’s a website, and they only know it as an app on their phone. And the new reddit interface is optimized for mobile, which is terrible and inefficient when browsing on a desktop.

It was the dumber, non Web 2.0 version of the site. It didn’t have any of the new UI’s user activity data harvesting apparatus or progressive loading features or fake posts (ads) or Adblock mitigation and so forth. It looked like a 2000s website but anyone who used Reddit in that era wasn’t going to care. Redlib is better if you need to check something on Reddit.

Easily blocked ads, no account required. No profile pictures. No "modern" UI that's slow and takes up huge chunks of whitespace for no reason. No stupid features like chat taking up space. No related posts taking up space in the comments. Also old.reddit supports custom CSS so every subreddit can have their own custom theme. Remove everything unwanted from the new site and app and you're basically left with old.reddi5

For me, it does not hide comments by default.

I like to read all the comments in one page load. No clicking tens of times to load all the nested comments

It's the only way to actually use the website in a reasonable manner.

Because new reddit is ten times worse lmao

I don't get it either. I exclusively used Reddit via third party apps. Never once had any desire to use old.reddit.

If you primarily read it on a desktop or laptop, which I think a lot of old.reddit users do, it's just better. Same reason I use old.lemmy: improved readability, more compact, less wasted/whitespace, less scrolling, it's just easier to consume.