This seems to be one of the best and most reliable ways to remove viruses.
Best answer by JimM
The method you're describing, while it will remove viruses in executable files, is limited by comparison to having the actual AV software installed on the system itself. Even then, we're looking at a post-infection scenario, in which while WSA will clean the system, it hasn't had the opportunity to journal and roll back changes the infection made. Which is to say, the infection will be cleared off, but it's more likely under such a scenario that some damage will already be done.
In fact, the best and most reliable way of protecting a system is to have WSA on it from the start. Then, not only does the infection get blocked at the point of entry, but also even in cases where WSA "misses" it initially, it will be fully able to roll back the changes made by the infection once it registers it as a threat.
This video explains how that process works:
The journaling and rollback is one of the main things that sets WSA apart from other AV software.
tl;dr It will clean off the infection itself, but you're much better off having WSA on the system from the start.