Maybe it's just because is Monday but, besides of the Julian Assange's example and the time capsule, I can't think of another use case of a Time-lock crypto puzzle, anyone?
You could do a delayed form of historical whistleblowing or confession, so that it doesn't cause you problems today, but history can know what really happened.
Perhaps providing the equivalent of a 'sealed envelope' to prove that something was known or happened on a given date, without having to be present or active to prove it.
It's fun to think of a puzzle, but presuming it was truly delivering on the safety promise, I can see quite a few uses. The real schemes though depend on a lot of varying factors, so in cases where the secrecy was critical, you can see why people wouldn't use it.
Here is one possible use case: imagine an offline digital cash system, so i.e. the bank will not accept the same token twice. To protect against an unscrupulous seller, the buyer pays by giving the seller a time-lock puzzle with the tokens; if the goods are not delivered by some deadline, the buyer will deposit the tokens at the bank, thus preventing the seller from doing so. Otherwise the seller solves the puzzle and makes the deposit. This is basically an anonymity-preserving escrow service, though in practice there are probably simpler approaches.
[0] http://qz.com/92786/more-evidence-that-data-thomson-reuters-...