These are meant for businesses. If a company reaches its seat limit or Microsoft detects the key is being shared publicly, it will be deactivated, leaving your software unlicensed.
This model is harder to pirate. While KMS emulators exist, Microsoft’s server-side validation is increasingly robust. If the cloud connection detects a fraudulent license, it can disable functionality remotely. Consequently, the "key" is becoming less relevant than the "account," pushing the black market toward credential theft (phishing) rather than license spoofing. free activation key for office 365