You are working with massive datasets where hashing time is a bottleneck. You need a fast hash for a hash map or lookup table.
If you are scanning thousands of files to see which ones have changed, xxHash is the clear winner. xxhash vs md5
For security: Yes, 100% dead. For non-security checksums: No, but it is outdated. You shouldn't choose MD5 for a new project today. If you need a non-cryptographic checksum, xxHash is better (faster and better distribution). If you need a cryptographic checksum, MD5 is broken, so you should use SHA-256 or BLAKE3. You are working with massive datasets where hashing