One of the use cases I have seen recently was driving down the total cost of DRAM in a larger-scale deployment of systems at AWS, Azure, Meta etc.
Pond [1] which is a memory pooling system, claims to achieve the desired performance and at the same time lowering costs as one example.
I think a look at the overall, bigger picture is important. For example considering how a system will be combined together with multiple GPU's, memory systems and other accelerators to meet the demands of applications, consider interconnects like NVLink [3] too.
For those interested, I have left a previous comment about experimenting with CXL on a local setup [0]
[0] https://news.ycombinator.com/item?id=37944691#37948761
[1] Pond: CXL-Based Memory Pooling Systems for Cloud Platforms https://arxiv.org/abs/2203.00241
[2] Intel Reveals the "What" and "Why" of CXL Interconnect, its Answer to NVLink https://www.techpowerup.com/254462/intel-reveals-the-what-an...
[3] NVLink and NVSwitch; The building blocks of advanced multi-GPU communication—within and between servers. https://www.nvidia.com/en-us/data-center/nvlink/