Some blogs write evergreen content, which don't quite require to note when each article was written. It's safe to say that a "blueberry pie muffin" recipe will remain unchanged for quite some time and it doesn't really matter when it was posted.
Other times, on blogs (such as this one) where it's important to note when something has happened, a post needs a date.
A perfect example: In this post we're talking about a new feature that we have just released. For the reader this might be important because they want to know when we have released this feature OR maybe they're curious about how often we're releasing new features.
In either case, you can now choose on each blog's Settings page if you want to show post dates on the Homepage or that posts specific page.
Some writers choose to hide them from the Homepage to avoid clutter and show them on that posts page only. The choice is yours.