I don't think we can be so certain as to what China sees as her needs. Perhaps her planners foresee scenarios in the not-so-distant future that there needs to be an intercontinental bomber to strike faraway targets without the need of using foreign airfields and without setting off ballistic missile alarms. I don't want to speculate what these faraway targets might be, as that would quickly escalate into a heated off-topic discussion.
Almost any target outside the range of 4500 km combat radius bombers with 2500 km range cruise missiles would likely escalate to strategic weapons rather quickly as I just don’t see PLAAF striking either ZA or BR for any strategic purposes.