A lot of people just need (or, to be honest, just like) having a couple added inches in height. I would wear heels except that I already have orthopedic problems- I wore them to my cousin’s wedding and it felt so cool to actually be able to see over people’s shoulders. They can also sometimes give a more polished, sophisticated look to an outfit than flats can.
One problem is that “in” heels now are usually either espadrille-style wedges (average about 5″) or stilettos- shorter and more sturdy heels are not really being worn very much. You’re limited by what they sell. Four inch stilettos are actually very chilled and orthopedically sound compared to what I see people wearing.