Oracle 10g has two new datatypes: BINARY_FLOAT and BINARY_DOUBLE that correspond to the IEEE floating-point types found in Java (and most languages).
Obviously, a big advantage is performance -- computers can crunch IEEE floating point numbers faster than binary coded decimals. But another key advantage in my mind is that the datatypes match that of Java, so there will be nothing lost in translation.
I came across this issue that suggests we need an Oracle10 dialect:
http://opensource.atlassian.com/projects/hibernate/browse/HHH-1961.
From a Hibernate+Oracle perspective, is there a preference?