Automatic revision saving is great. If you turn that off because you think it makes your database slow I think you maybe probably have bigger problems maybe.
✅ Posts are obviously useful. ✅ Pages are obviously useful. But there is more! Custom Post Types means you really do whatever makes sense for your site.
Things I do in comments: • Markdown / Preview (Jetpack + Plugin) • Feature/Bury (Plugin) • Heavily moderated and encourage good behavior • Offer notifications for follow ups • Offer newsletter signup • One-level threading