Virus getting through?

I am curious, why does mailinabox “fail” this virus test, or is this test irrelevant?

I don’t believe there is any virus checking mechanism such as CLAM on MIAB.

It probably would be a useful addition.

Are virus emails still relevant for business class windows users or was that a thing of the 90s? I am just wondering how obligated I am to provide a email virus scanning service to my clients nowadays. Lol