What benefit does just a Hearthstone give?

I'm a little bit unclear on hearthstones in Exalted 3rd edition. If a player buys just the Hearthstone merit (so no Manse, and no Artifact in which to socket the stone), what benefits do they get? I remember 1st Ed Hearthstones being really cool, but I can't quite figure 3e ones out. The rules - which I have read, but which are somewhat sprawling, so I may have just missed something - don't appear to be explicit.

Some hearthstone descriptions explicitly mention socketing, while some don't - can I assume the latter type don't need it?

Is there any kind of Essence trickle like in previous editions? In fact, I'm not 100% sure what the rules are on Hearthstone-essence-trickle even if socketed and/or accompanied by Manse ownership.

• I also cross-posted this to the Onyx Path forums, where it also got answered similarly (but not identically) to @saelvarath below. I've... misplaced the link, but will add a summary when I refind it. – Chowlett Jul 10 '18 at 14:43