Why do we need freedom?
You might want to begin by parsing the question to consider what types of freedoms you are referring to and the antecedent of the pronoun "we."
No individual can live in perfect freedom in the world because that would infringe on other people's freedom. For example, if you want your neighbor's iPhone, you cannot steal it without impinging on your neighbor's freedom to own his own phone. When driving, you are not free to run red lights. In order to live together in harmony, people accept restrictions on their freedom.
All civic societies must balance rules made for the common good which restrict certain freedoms with citizens' desires for liberty. Although post-Enlightenment western societies valorize individual freedom, many other societies subordinate freedom to other social goals, including security and order.
Many modern western societies consider free speech an essential part of the democratic process. Not all countries are democracies, though; the Chinese government and Gulf monarchies would argue free speech destabilizes political systems and leads to unrest, rather than promoting peace and prosperity.
The freedom to travel is something many people enjoy, for business or personal reasons, but travel is restricted because the world is divided into nations. One must get permission to cross national boundaries, with some nations' borders being more restrictive than others. This enables countries to control immigration and is also an important part of national security. Even locally, you are not free to trespass on private property.
I would argue we do not need freedom in a general manner, but rather that there are certain freedoms certain people desire, but these are always balanced against various restrictions necessary for social and political associations.
Freedom is a basic necessity for healthy survival of human species. Freedom can be of several types, freedom of speech and thought, freedom of action, freedom to live and work anywhere, freedom to grow, etc. There are societies, where sections of population cannot speak freely and their words are censored by authorities, under one pretext or the other. Human history of full of such instances. Without the freedom of speech, how can we express our thoughts to each other and grow intellectually and collaborate? Without freedom of occupation and ability to work anywhere, how can we start a business and work towards its success? Science and business require successful exchange of ideas and ability to work collaboratively. Without the freedom, both science and business will suffer and so would the life of citizens , in general.
Hope this helps.