Once your CSV (or TSV) files start having quoted fields, they become very tricky to parse using standard multi-purpose tools like sort, awk, & uniq.

It's hard enough when you have delimiters in quoted fields, but dealing with quoted newlines starts to become unreasonable, especially for line-based tools.

CSV files, as you say, are absolutely wonderful to create. Problems come up when you try to parse files other people write. Not everyone follows RFC 4180.