I loved your question because no -  none of us really need makeup -  humans lived for thousands of years without it.  But...... many women love it, find it an affordable luxury, it's fun, and it can be protective (like sunscreen in foundation). 

The reason that many British women have lovely skin is that there is no sun where you live!!!  Your climate is a lot like Seattle, a soggy, rainy, long winter with very little summer. If you have friends who regularly go sunny places to bake, you'll notice the difference especially past 35. PS - it stll helps your skin to use a light sunscreen every day, even in the winter.  

Dr. I