Foot orthotics or supports are made to correct biomechanical problems of the feet and to help the biomechanics of the foot. There are several different kinds of foot orthotics and methods of making them for podiatrists to use and select from. Some people need and do benefit from made to order foot orthotics while some may be helped by the easier and cheaper mass-produced foot supports. Which one is best for each individual is determined by exactly what is leading to the problems and what the treating specialist proposes is right for that person. Many different foot orthotics have unique design characteristics and a good doctor will attempt and match those up to the needs of the individual. If that is not done properly, then there might not be any kind of improvement in the problem.
Foot orthotics aren't without their issues. When they are not the right choice for the individual, then they won't work. You are also constrained by what shoes you can use, in that you have to be able to fit them into the shoe and there might not be adequate space. There are also kinds of shoes, for example the flip flops which they just can not be used in. This could pose a problem in warmer places which make closed in shoes necessary for foot orthoses uncomfortable. There are alternatives, as an example, the Archies that have a foot support built in. The design of the arch supports in these flip flops are similar to what you would get in an over-the-counter arch support, but probably not as good as what you would get from a customized foot support. Using these do provide a practical option to foot orthoses, depending on where one can wear them and the character of the biomechanical issue. If you do need foot supports there isn't any harm in trying these kinds of choices or raising it with your treating doctor to see what they believe.