A corrupted activation system leads to BSODs (Blue Screen of Death), application crashes, and high CPU usage. The fake KMS server running in the background constantly phones home, consuming resources.

: Esses programas podem causar lentidão, travamentos frequentes e comportamentos anormais ao modificar arquivos vitais de inicialização do Windows. Bloqueio de Atualizações

You still receive all security updates forever. For a gaming PC or a secondary workstation, this is often the smartest choice. You are paying nothing and risking nothing.