I think that this question might be considered in two parts: why is it important to study and understand the literature from any historical period, and why, particularly, the Victorian? The first, more general question considers the variety of human experience, the differences in the beliefs, norms, morals, and values of people in different historical time periods, and the commonality of the human condition through time. Any historical period other than our own offers us a different view of life; a study of colonial New England, for example, would reveal a prejudice against worldly consumerism that is unlike our own age, for example, coupled with an nearly universal religious intolerance that we would find both alarming and familiar (in this age of religious terrorism around the world). There are vast differences in the beliefs of the people from other times and places from our own views of life, and then there are startling similarities. The ratio varies with each time period and geographical place, of course, with the more remote time periods, perhaps, showing us greater differences and fewer similarities, but there are certainly similarities in every age and place that can be enlightening to the study of our own time. One only needs to review the Code of Hammurabi, a law text over 3700 years old, to see that many of the crimes that we abhor today were abhorred then -- and that some of the punishments for those crimes would not be considered humane by any of us today!
But how does this relate to Victorian England? If we are to assume that every historical period's literature can have something important to teach us about that time (and, by reflection, our own) what is so important about the reign of Queen Victoria? For Americans of the century before our present one, Victorian values were held over long after the queen's death in 1901. Her reign was very long (63 years) and, during that time, many moral and social customs became refined and codified. There were certain changes during that long time period, doubtless, but the social values of that time were surprisingly resilient, and they formed the basis of much of the value system of the first half of the twentieth century in America (which emulated Britain, and other European countries, in many ways in those days). After that time, those mores and social customs became the things that Americans rebelled against. So by any measure, positive or negative, the beliefs and practices of this time are relevant to us today.
Specifically in regards to women, the Victorian era created some surprisingly durable values which still influence us today. The rigidly strict social restraints on women, and the insistence on their total propriety and self-denial in all sexual matters (as exhibited in Jane Eyre) has had a lasting effect on how we think about women. Before the codification of "middle class" morals under Victoria's reign there was not nearly so much scrutiny of women's behavior as there was after it. This lasted long into the twentieth century, well into the 1950s, and only began truly to be rebelled against in the 1960s in America. For this alone, the constraints put on Jane (and other women of her class and situation) during this time period are interesting and important to us -- to know where these ideas, which were rebelled against, but, in some ways, are still with us, came from in the first place is doubtless valuable.