Just as importantly - it was an all‑in‑one. I think a lot of people tend to forget that there were already plenty of earlier BASIC dialects (GW‑BASIC, Apple II BASIC, C64 BASIC, etc).

However QBASIC was likely the first freely available, all‑in‑one "batteries included" environment that came bundled with MS‑DOS 5 with a relatively friendly IDE that had built‑in help for every single command. GORILLA.BAS and NIBBLES.BAS were the gateway drugs for many future programmers.