I was one of the folks who voted on this, and was actually looking to be able to type “every weekday” when creating a task to have that automatically set it to repeat on week days.

I'm really sorry about the delay, I've just seen this post! This is actually already possible in Actions, the trick is that you have to choose "Weekly" then the days of the week you'd like the Action to repeat on:

This is absolutely necessary, the fact that this isn’t in place makes me wonder if I’m the only person using Actions for work?!

Definitely needed I would like to be reminded of a task that I need to do every Thursday.