My impression is that its invention was for the sole purpose of eradicating the idea that Windows is insecure and prone to viruses, which explains why it can be overzealous and CPU hungry.
I would only enable it for family members who don't know what they are doing. For some reason, I haven't needed any form of active virus scanning in something like 15 years. If it turns out I've been infected this entire time, the criminals sure are taking their time stealing my money, etc.
I think this would describe the majority of computer users. And the majority of computer users are also using Windows.
> I haven't needed any form of active virus scanning in something like 15 years
Microsoft Defender antivirus was released alongside Windows 8 in 2012. And it's essentially a rewrite of Microsoft Security Essentials which came included starting with Vista. If you haven't been explicitly disabling it, which your comment sounds like, you've been running one without knowing it for 16 years
Not quite.
Windows Defender was released together with Windows Vista, this was very rudimentary and only handled malware and spyware not unlike Malwarebytes, it did not handle viruses.
Microsoft Security Essentials was released standalone sometime during Windows 7's era, this was fully fledged anti-virus.
Microsoft Security Essentials was renamed Microsoft Defender and bundled with Windows starting from Windows 8, where it has stayed to this day.
The version of Windows Defender that came with Vista was a bit different and included realtime scanning when executables were run.