In this comparison, you probably can't tell the difference between identical images taken on a medium format and APS-C camera. But that doesn't mean that medium format cameras are a waste of money. As with most questions like this in photography, it really depends on what type of images you make and what you plan to do with them.
Viewed digitally at full size, it takes a very trained eye to be able to spot the differences, and even then the Fujifilm file doesn't necessarily look better in this viewing scenario. What we should learn from this is that as photographers, we should put more thought into our selection of a camera system. Many photographers purchase very expensive top-shelf cameras and lenses, yet only share their images on social media or their website, which means you are only ever seeing a down-sampled, lower resolution image. This means that you probably only need a full-frame or medium format camera if you plan to print your images large or to meet commercial client requirements. There are also many benefits to using cameras with smaller sensors, such as faster burst shooting, lower cost, size and weight savings, and wider depth-of-field.
If you are interested in learning more about the pros and cons of different sensor sizes, be sure to check out Which Sensor Size Suits Your Type of Photography the Best?