If you only take four economy flights on BA then you only get 2 CCR visits out of being GGL/CCR, assuming they're returns anyway.

As OWE you'd have been in the Flounge no matter what your home programme was.

As such if you're not flying BA, you're not getting pampered.

In return you've highlighted yourself as a high value customer who BA should be capturing. As such the cost is low but BA can potentially get a lot of business out of you.