Reality: A legitimate license ties to your Microsoft account and hardware hash. If you replace your hard drive, you can reactivate instantly. With a pre-activated ISO, if Microsoft issues a blacklist update (KB971033), your activation dies and you cannot get it back without reinstalling malware.
Because the ISO is a "cracked" file, it has no digital signature verifying its safety. Malware distributors often embed: Windows 10 Pro 64 Bit Pre Activated Iso Download