I think there are various aspect to the importance of the German colonies.

Economicly they were planned to be a new market for the rapidly growing German economy. It was thought that many of the new products that were being produced could be sold in the colonies instead of at home, where many workers were too poor to afford the products they enabled. This however did not work. In fact from a buisness standpoint the German colonies hurt more than they helped. It was far to expensive to settle people there and to build up the necessary infrastructure that would have need for, say, spare parts for a spinning mashine. The local indigenous population usually didn't have much interest either. I can get some statistics for that if you'd like.

The prestige of oversea colonies however was nothing if not tremendous. The third Kaiser, Wilhelm II. for example was known for believing that "Germany's future is on the sea." So yes, puplic attention and pride was definetly there. Take for example the Boxer Rebellion in China that aimed to expel all European, Japanese and American foreigners. When the Boxers killed the German Envoy Clemens Freiherr von Ketteler there was great outrage. In the international Forces who responded German Troops made up the largest contingent and led the war effort in many ways. As for the public sphere look for expample at these postcards form the time:

https://www.dhm.de/lemo/bestand/objekt/krieg-in-china-1900.html "The War in China: We give him a good beating, hipp hipp hurrah!"

http://www.dhm.de/fileadmin/medien/lemo/images/96002038.jpg "The War in Cina: Now listen up, or we will do this the hard way."

That being said, I can't really say if the german goverment or people cared when these colonies were lost. It happend quite fast as well; Like i said, urbanised life never did take off. By then Germany was locked in a world war. I assume most people had bigger worries at that point, however, I might be wrong.

I should add as well that most of my knowledge is about the African colonies, not as much about the Pacific ones. But all things considered, most of what's been said should apply there as well.

Hope that helps!