Wood pulp-which produces paper-comes from softwood trees such as spruce, pine, fir, larch, and hemlock trees. Wood pulp also comes from hardwoods such as eucalyptus, aspen, and birch trees.
It is hard to say for sure, but several of the smaller minicomputers of the 1960s (e.g. DEC PDP-8) could and usually did sit on a desktop. However the term "desktop computer" was not created until the microcomputers of the 1980s and did not come into common usage until laptop microcomputers computers became widely available in the 1990s.
Initially it was invented for security agencies (specially military) communication and correspondence. It was the most secure platform as nobody knew anything about it. So, it was easy for security persons to share information with different stakeholders.
The computer's invention has been detailed as to why it was invented that answer is possibly because the people of those days wanted to invent a machine that could aid them in simplifying complex calculations. Even today the invention is the continuous process. It has not end. After some centuries may be computer will called with something different names other then the word 'Computer'. It's all that need. "Need is necessity for invention". The present computer technology will become history and more advance technology will reveal to us in near or far future, but the milestone of today computer technology will only be responsible for future so called 'computer'.