It's good for a garden but not for a pond. I enjoy swimming better in ponds with sand or clay bottom. Another disadvantage of it is that this soil isn't predictable. What does it mean? Some part of it can simply rise to surface - such things happened in the past and that's why it has to been removed until the clay is reached.
An advantage - usually it can be found in very wet places - it's doubtful that such pond could dry.
