Thanks. I similarly solved it via a Workflow. But it is something so basic that it should be one of Alfred's built-in actions.
Right. What we want is not the last command, but the result of the last command, whatever that may be.
Another example: As in Alfred, you can use QS to quickly perform calculations. But in QS, when I activate it again, the result of the last operation, i.e. the output of the calculation, is selected by default. Thus, I can perform further calculations with the output. In Alfred, ↑ recalls the last calculation, not its output. That is fine, but it starts to get hairy as your calculation gets longer and more complex. Now, this is just a simple example, and it is easy to get around this limitation, as you can simply paste the output value that Alfred copied to the clipboard. But it demonstrates the power of the concept of being able to select as input to Alfred whatever was the output of the last command. It allows you to quickly chain commands.
Thanks for the tip.