It will deliver an improvement in graphics performance for most use cases if you’re using any current Apple machine but the iMac Pro or the top-spec 27-inch iMac. But with no upgrade potential, it’s a tough sell for almost everyone. The whole point of an eGPU enclosure for many prospective buyers is to provide an upgrade path for the GPU you’re using with your MacBook Pro or iMac.
This is one area where Apple’s usual approach just doesn’t make any sense. Most users who would be drawn to an external enclosure want a beefier GPU than this, and a lot of them want upgradeability. The discrete GPUs in the MacBook Pro and iMac are good enough for all consumer uses except heavy-duty professional graphics work and triple-A gaming. An eGPU enclosure should solve for those cases, but this one just doesn’t.
If I still lived that MacBook Pro + external display life, I’d be looking at an eGPU, but probably not this one.