Absolutely crazy I hadn’t run across this little gem yet… could’ve used that bugger to get out of a couple jams.  e.g. eliminating heavily duplicated xml blobs that represent incoming supply chain events/transactions.  The BOL has a couple examples to get your juices flowing.  e.g. Run it on a column list, CHECKSUM(*), to compare rows.  There’s also BINARY_CHECKSUM(), HashBytes() and CHECKSUM_AGG() for different slices.