Wearing high heels takes balance. Most people have an excellent sense of balance when they are young. Some, however, do not. For those whose sense of balance is in question, but they still love high heels, platform high heels may be the alternative they are seeking. You still get the benefit of high heels, but you have the added benefit of extra assistance.
Platforms have the whole foot supported, which protects the wearer from harming their foot with a single thin heel. If you fail to lift your foot exactly right or sit it down right, you could easily harm your foot. At that point, you would be injured and unable to wear high heels.
Platform heels are an excellent solution to the most common problem surrounding wearing high heels as you get extra support and its harder to injure yourself.