Learn Dutch: Zij is naar de pinautomaat gelopen om te pinnen. - She walked to the ATM to withdraw money.

This is exactly how verbs of motion work in Dutch! Because she is walking to a specific destination (naar de pinautomaat), we must use zijn as the helper verb. If she had just been walking around for exercise without a specific destination, you would use hebben and say Zij heeft gelopen.

Why do we use om te pinnen here instead of just voor pinnen to mean "for withdrawing"?

In Dutch, when you want to express "in order to" do an action, you must use the structure om te + the infinitive verb. You cannot use the preposition voor directly with a verb to show purpose, even though it feels natural in English to say "for withdrawing".

Does the verb pinnen always mean withdrawing money from an ATM?

Not always! It literally refers to using a bank card with a PIN code. In the context of a pinautomaat (ATM), it means withdrawing cash. However, if you are at a checkout in a supermarket and they ask "Wilt u pinnen?", they are simply asking if you want to pay by card.

Why does the past participle gelopen end in -en rather than having a -t or -d ending?