Blizzard’s decision to omit an offline mode is not an arbitrary restriction. It is a fundamental architectural choice tied to how the game operates. 1. Shared World Architecture

While you cannot play the game without a connection, you can set your Battle.net status to "Appear Offline"

Furthermore, the game utilizes a seamless open-world format where players frequently cross paths in towns, collaborate on spontaneous local events, or team up for massive world bosses. From the perspective of modern game design, forcing players into an online ecosystem ensures they are constantly exposed to the live-service framework, including seasonal updates, battle passes, and the cosmetic microtransaction shop.

Even with a high-speed connection, server-side issues can cause "rubber-banding" or disconnects, which are especially lethal for Hardcore characters .

Whether on PC or console, the game maintains a unified "Games as a Service" (GaaS) model. The Player Dilemma