The allure is obvious. A 72MB file means you can put it on a floppy disk (technically, you’d need a few) or a tiny USB stick. The idea is to boot it on ancient hardware—Pentium 3s, 256MB of RAM, old Point-of-Sale systems—and get a functional GUI.
If you manage to find a real version (usually a modified "MicroXP" v0.82 or similar), here is what you get: windows xp lite iso 72mb portable
Modified ISOs found on third-party file-hosting sites are primary vectors for malware. Because these ISOs are unauthorized redistributions, there is no checksum verification against the original developer's hashes. The allure is obvious