The phone's screen cycled through a canned demo that showcased some of the device's features and functions. None of the demos appeared to make use of wireless capabilities however, so it didn't provide much insight into what the super-fast 5G wireless data experience will actually be like.
Samsung's upcoming Galaxy S10 is said to have have a hole-punch cutout on the top right of the display. The prototype's corner notch isn't the same thing, but it does show that Samsung is at least experimenting with moving selfie cameras and sensors to a different location away from the top center of its phones.
All we can assume about a 5G smartphone from Samsung is that it'll include the 5G-compatible model of Qualcomm's Snapdragon 855 mobile chip. What kind of speeds and performance we can realistically expect from mobile 5G vary greatly. It's generally expected that mobile 5G networks will be significantly faster than the current 4G LTE networks we currently use to stream data on our smartphones today.
We'll have to wait and see for a true 5G smartphone connected to a 5G mobile network to find out just how much better 5G will be than what we have now.