There are benefits to sickness, according to the puritan, Jeremy Taylor [Holy Dying]. Consider:
Truth is, there are but two great periods in which faith demonstrates itself to be a powerful and mighty grace; and they are persecution and the approaches of death…By the faith of the promises we learn to despise the world, choosing those objects which faith discovers; and by expectation of the same promises, we are comforted in all our sorrows, and enabled to look through and see beyond the cloud: but the vigour of it is pressed and called forth when all our fine discourses come to be reduced to practice. For in our health and clearer days it is easy to talk of putting trust in God; we readily trust him for life when we are in health; for provisions when we have fair revenues; and for deliverance when we are newly escaped: but let us come to sit upon the margent of our grave, and let a tyrant lean hard upon our fortunes and dwell upon our wrong, let the storm arise, and the keels toss till the cordage crack, or that all our hopes bulge under us and descend into the hollowness of sad misfortunes; then can you believe, when you neither hear, nor see, nor feel anything but objections? This is the proper work of sickness: faith is then brought into the theatre, and so exercised, that if it abides but to the end of the contention we may see the work of faith which God will hugely crown.
Words of Grace 