Enter the age of excess.
Mattresses somehow overnight got bigger and bigger as competition for customers raged between brands. Someone in marketing figured out if you make it bigger, you could charge more, because there was the perception that you were getting more value. But just why are some mattresses bigger than others, and do you need a bigger, taller, mattress?
Memory foam mattresses and organic mattresses and beds alike have gotten taller and taller. Usually, however, there is not more memory foam to make your mattress taller or bigger, there is usually just more of the base material. The same goes for taller or bigger coil mattresses. Some have even added another layer of coils. Usually, however, the comfort layer, or memory foam layer, is about the same thickness as the thinner, smaller mattresses and beds.
No, height does not matter. Usually you are paying for more prestige and looks, not necessarily support and comfort. A mattress, whether it is a memory foam mattress or latex organic foam mattress, can range from 6" tall to about 12-15" tall. There is more than enough support at those sizes to support and last a good long time.
When you are shopping around the San Francisco Berkeley Albany Oakland San Rafael San Jose market at the mattress stores in our area in the Bay Area, you will see some really thick mattresses, up to 24" tall. At Nest Bedding in Albany California, our tallest mattress sits about 15" in height, while our shortest mattresses are in the 7" to 10" range.