Trump berates Danish PM over Greenland in ‘horrendous’ phone call

Denmark is normally otherwise an ally of the US.

However, this call has spooked the Danes. There will 100% be escalations from the Danes to protect themselves as a result.

Everyone knows Trump is a dick, and the US is mega powerful. The debate in the rest of the world is how to deal with it. Using "honey" and using "vinegar" are both in the running. Honey remains more popular because chummyness is an old reflex with the US, and most well-to-do Westerners still don't get what's happening.

Why is Denmark even offering anything at all

As others have pointed out, the US play here is likely to be stopping payments for the current US military based in Greenland but not leaving, testing its limits (operating outside of the designated areas), and generally just begging for a response. At this point the Danish (and the EU generally) will have to choose - if they do nothing then it'll encourage more of this BS in Greenland and elsewhere. If they respond with any force it'll be what Trump wants. He'll use it as pretense for...whatever he wants to do.

This behaviour will make it far less likely that all of the US international partners will renew military base leases or sign new ones, and long term it will diminish American military power globally, but nobody in MAGA let alone Trump are really thinking beyond the immediate anyways.

So the answer your question, the Danes are trying to avoid all of that BS.