Some do some dont. Mostly dont.
I dont think the benching helps that much, (according to many sources inc sportivny press, pressing causes detriment to jerks) but many lifters like to get a little swole up top to match their squat legs. If an oly lifter wants to do some pressing work, surely it would be better to do it overhead anyway? In the form of presses, push presses, bnp presses, push jerks etc... Chinese lifters do a lot of those.
I started push jerking since I tore my labrum and cannot do normal pressing. A very fun exercise.