To the extent that we, each of us as individuals, understand what reason is, have learned how to identify, engage and derive the benefits of the process, we are here in our capacity as rational beings by virtue of reason for that and no other reason alone. To know why we are is to understand how we are what we are which determines who we are and ultimately what we can and should become.
No, reason is not merely an end in itself but a means to determine what ends can be reached and to discover the available means to reach an end that will be meaningful and worthwhile by virtue of its meaning. In embracing this, the next step in our ongoing evolution, becoming the eyes and ears by which the universe becomes not merely conscious but self-aware, we in concert with the universe that made us possible achieve a purpose as well, a recognition of the importance of our mutual existence, that of providing a realm in which and means through which reason might become manifest and prevail.
Apart from and devoid of reason there is no reason . . . for anything.