Ballet flats really are a particular shoe type prompted from the shoes used by ballet. By design these footwear are extremely minimalist. They do not much on the foot other than protect it and are available in a wide range of good looking styles. Additionally, they are typically rather tight fitting that can help the shoe stay with the foot. There is nothing inherently wrong with these types of shoes so long as they usually are fitted appropriately and are also of the correct size for the feet.
The challenge using these minimalist categories of footwear is when there is a foot condition that has to have some kind of arch support, even on a temporary basis. The key kinds of conditions that this might be required are especially if you are on your feet throughout the day and the feet and legs get very fatigued. Due to the minimal nature with the style and also the usually tight fit of the shoes, there is not probably going to be much room within the shoes to try and do a lot. Medically, alternatives or options might be reduced if you spend most of your time in this particular footwear. There may be simply no manner in which a typical foot orthotic will probably squeeze into these types of footwear. In some cases a reduced down foot orthotic might be able to fit into the shoe. In other cases the condition could be managed by changing to an alternative style of footwear which foot supports can easily be used in for short time up until the problem is fixed. It will always be better to see a podiatrist and discuss the choices that you have when you actually do need some kind of support and if it might be fitted with your ballet flats style of shoes.
There's a limited types of ballet flats that can be purchased which do have some arch support kind variations that are part of the shoe. Nevertheless, they are hard to find and might not be ideal for you. You can find the instant arches types of self adhesive padding that could be placed inside the shoe to give some sort of support and this is commonly a fine solution if that is just what ought to be needed to deal with your condition. Podiatrists do employ them sometimes if you have no other suitable alternatives to getting support in to a ballet flat type of shoe.