Except there are a ton of people (as in millions of them) who have smartscreen disabled because they're using a non-microsoft antivirus program. So no, this is a non-issue.

Also, smartscreen is not a naive block of unsigned code. Code blocking is reputation based, and people disabling smartscreen and running a binary contributes to that reputation. Which means that people like gp are actively helping by continuing to use Windows and running safe-but-unsigned apps. So, to reiterate, not an issue.