You cannot put milk in this machine - unless you fill the water tank with it, which can get quite unhygienic.

The machine has only one water tank. If you want a cappuccino or other milk drink, you have to hold the milk in a jug under the "frother" (tube to the left of the coffee outlet).

So to answer your question exactly: yes, you can also let coffee out when there is no milk in it ;)

I don't really understand the question... It's an ordinary coffee machine with a separate hot water/steam outlet that can be used to froth milk warm. But it's not absolutely necessary.