It was a design choice; for some actions it's possible - click being a great example - for others it's not e.g. hover; are you thinking, or actually hovering? ...waiting: are you thinking or trying to add a wait to the test?
So, we went the route of having the same way of doing things for everything. We may change this in the future, but at the moment it's consistent and easy to learn. You add an action, then run it - no need to do it twice, or learn multiple ways of doing things.
