BA does not grant status-based freebies. BA uses UG's as a marketing tool, largely to give a taste of the premium product to people who generally do not use it. If the marketers are correct, the passenger who would never have spent money on a premium cabin, savors the experience and then cannot live without it.

This all requires sophisticated mining of the data which BA possesses. Generally speaking, people with status fly BA more than others, but this does not mean that they are likely to spend more going forward.

Ask yourself whether, if you were UG to Shangri-La Class, whether you would purchase it in future or simply be happy for the UG. if the former, you are a candidate for an UG.