In fact, itโs actually better to pirate them and use Plutonium for Multiplayer. This is due to the fact that many pre-Infinite Warfare Call of Duty titles have unpatched RCE vulnerabilities that Activision never bothered to fix, but have been in Plutonium.
https://nvd.nist.gov/vuln/detail/CVE-2018-20817
https://www.cvedetails.com/vulnerability-list/vendor_id-2190/Activision.html