Update README

README.md

@@ -295,8 +295,8 @@ e.g. `projects/your-project/topics/bitcoin_blockchain`.
 - The command saves its state to `last_synced_block.txt` file where the last synced block number is saved periodically.
 - Specify either `--start-block` or `--last-synced-block-file` option. `--last-synced-block-file` should point to the 
 file where the block number, from which to start streaming the blockchain data, is saved.
-- Use the `--lag` option to specify how many blocks to lag behind the tip of the blockchain. It's the simplest way to 
-handle chain reorganizations.
+- Use the `--lag` option to specify how many blocks to lag behind the head of the blockchain. It's the simplest way to 
+handle chain reorganizations - they are less likely the further a block from the head.
 - Use the `--chain` option to specify the type of the chain, e.g. `bitcoin`, `litecoin`, `dash`, `zcash`, etc.
 - You can tune `--period-seconds`, `--batch-size`, `--max-workers` for performance.