"Downloading" a generator often means installing keyloggers or trojans that can compromise the user's entire computer, not just their game account. Impact on the Game Economy

From a developer's perspective, KR generators represent a threat to the game’s sustainability. Krunker relies on the value of its economy; if players could simply generate currency, the market for skins would collapse, and the developers would lose the revenue needed to maintain servers and release updates. This is why (the developers) actively bans accounts associated with cheating or exploiting the currency system. The Ethical Alternative

Some generators require login credentials. Providing this information gives hackers full access to the account, allowing them to steal skins or sell the account.