: If even one byte is missing from Part 1, the entire extraction will fail, wasting your time and bandwidth.
When large games are uploaded to file-sharing sites, they are often split into smaller "parts" (e.g., Part 1, Part 2, Part 3) to bypass upload limits or make downloading easier for those with slower connections.
: Many sites hosting split .rar files bundle them with adware, trojans, or "download managers" that infect your PC.