Yes, it's very similar! However, hledger's posting dates are a little more flexible, as you can have anything from no additional dates to one date per individual posting (debit or credit) in the transaction. This might perhaps be useful if you have complex split transactions where a balance is settled by multiple payments.

Just recently I bought an item on sale for 15 Euros with a card in Sterling (my bank did the currency conversion). Pretty much immediately after paying, though, I exchanged it for a different item for 25 Euros, making up the difference in cash. The cash is obviously 'cleared' instantly but the card payment could clear later. That said, in this case it happened to clear the same day anyway so no special posting date was required.

  2025-08-10 Redacted
  Expenses: Redacted  13.03 GBP
  Expenses: Redacted     10 EUR
  Assets: Bank       -13.03 GBP
  Assets: Cash          -10 EUR

I suppose the main question is at what point these splits become complex enough to create a dedicated liabilities account specifically to track the payment of that one expense, à la accounts payable, which you can of course do with any plain text ledger.

They are different - though often tried for the same kinds of use case. Here's https://hledger.org/hledger.html#secondary-dates (hledger's name for effective dates) vs https://hledger.org/hledger.html#posting-dates. (Both features come from Ledger.)