Order blocks: do they add anything beyond classic levels?

An order block is the last candle before a big move — supposedly where institutions left unfilled orders. The concept is popular in ICT-style trading and hotly disputed everywhere else.

What's your verdict?

• whether you trade order blocks and how
• how they differ from plain supply zones in practice
• the evidence that convinced you either way

Keep it civil and test-based; anecdotes are welcome, certainty is not.