Before 1.9, PvP (Player vs Player) combat revolved around "spamming" the click button. The fastest clicker won. This was fast, chaotic, and required high CPS (Clicks Per Second).
Beyond security and legality, there is a social aspect to consider. In Minecraft communities, cracked players are often looked down upon. On the rare servers that allow offline mode, players using cracked clients are frequently: Minecraft 1.9.1 Cracked
The long answer requires weighing a temporary $27 saving against the permanent risk of identity theft, ransomware, losing access to your main computer, and being excluded from 99% of the multiplayer experience. Before 1