All are used for bonsai. The 'oaks' are very different from e.g. English or even pin oaks, but are great for bonsai. Growing quickly is not a bad thing at all as most of us wish our trees would grow quickly so that we can then (as is done for most bonsai) cut them back to regrow new branches, and have the older, fatter trunks to make them look mature and interesting. Bonsai are usually not grown "up", but chopped down and then worked on in various ways to get them to look like grown trees rather than "sticks-in-pots".