Preserve your system. Respect the developers who built this masterpiece. And leave “Version 1000” where it belongs — in the trash bin of internet history.
Pros
Legitimate digital retailers (like Steam, EA App, or Epic Games) sell licenses directly to your account. They do not typically email you a "serial number" unless it is a legacy CD key for a very old game being sold by an authorized reseller (like GOG or GreenManGaming). Preserve your system