19 inch high handicap toilets are not a problem for several people. It happens because they feel comfortable while using it. Well, actually when designing a toilet, the designer has to consider about the average of people height. On the other side, they have to decide about who will be the one to use it. It is better if the design can be used by more people.
19 inch high handicap toilet will be a problem for people whose the height needs the more toilet height. When you sit on it once the height is not right, you will feel like something wrong is about happening to you that you have any problem to feet on the floor.
On the other side, it will be a problem for people whose the height is not supported to use the toilet. One of those people is a kid.
19 Inch High Handicap Toilets pic from homeability.com