Why Comparing Hashes Beats Comparing Files Directly
Verifying that a downloaded file matches what the publisher intended is exactly what a published hash checksum is for — but comparing two potentially large files byte-by-byte is slow and impractical, while comparing their much shorter hash digests is instant and just as reliable, assuming a secure hash algorithm (see Complete Guide to Hash Functions for why MD5 specifically is weaker for this than SHA-256).
A hash comparison tool exists because manually eyeballing two 64-character hex strings for an exact match is genuinely error-prone — a single transposed or misread character is easy to miss visually, especially in a long string, and a hash that's off by even one character represents a completely different (and potentially tampered or corrupted) file, not a "close enough" match.
This matters most after downloading software from a mirror or third-party host, verifying a file wasn't corrupted in transit, or confirming two copies of a file are genuinely byte-identical without needing to compare the full file contents directly.