You might be more likely to get a useful answer if you explained what the tag does in weblogic. I assume you are aware of the spec-required commit options A, B, and C.
I assume that weblogic ignores option C and leave the instance in ready state. Not valid according to spec, true. But if you know that you do not share the db with anybody else it would be a performance boost to avoid the sequence ejbPassivate --> ejbActivate --> ejbLoad just to get back to the same state again.