What's the beef against shoe inserts? It's personal preference. Not everyone can afford shoes with arch support build in, such as Saint Crispins or Meermin. Shoe inserts could make flat insole shoes more comfortable by providing cushioning or other support functions.
Besides, for some country shoes or hiking shoes it makes no sense to buy with any arch support. Especially for those who sometimes wear two layers of hiking socks and sometimes wear simple sports socks.