More like a vulnerability scanner. Signature based antivirus apps are mostly useless nowadays, but being able to tell me I'm running a broken version of OpenSSL is very useful.

Also, beyond what Karunamon mentions, i want to scan my network, my IoT devices, etc.

Besides, virus scanners are heavy and ugly, i've always hated them. Sure, it's nice to have monitoring of a breech, but why do i have to sit with holes in my security waiting for a breech? Some virus scanners try to monitor downloaded files or weird behavior etc, but i'd much rather scan my computer for holes, than things that have already exploited the security vulnerabilities that i had open.