Why are people doubting this? This opens up massive possibilities for people, especially those who want to start businesses outside of city centers.
You could:
host your own home-servers and never be worried about bandwidth
get 8k streams and not stutter (a low-end 8k stream requirs 50Mb/s, a family of 4 would need minimum 200 Mb/s just for videos)
send 8k streams and not stutter
offload most of your data to a datacenter on the other side of the planet and not worry about access speeds
boot into a browser or a minimal frontend with a low powered device and mount your home directory
offload computing to the cloud (no need for a gaming PC if you can just play them online)
The biggest thing would be 8k streams. 360 8k streams would be even crazier. 360 videos are filmed using 3-6 cameras depending on how much fish-eye you want. True 360 requires at least 6. If each is filmed at 1080p that's ~6k total resolution, but since you're only watching one section of the video at a time, you're really seeing 1080p.
Those "8k 360 videos" up on youtube are a lie! They aren't 6x8k, but most likely 8k / number of cameras. True 360 8k video would be 6x8k cameras.
A single 8k stream at minimum requires ~50Mb/s. Multiply that by 6 and you're at 300Mb/s just for a single 360 8k stream. Family of 4 --> 1.2Gb/s just for everybody to watch that content - and that's the minimum. If you have a higher bit rate and aren't streaming a 30 fps, you can quite easily double or quadruple that. Family of 4 again means 5Gb/s if everybody's watching that kind of content in parallel.
But this is just the beginning. Why stop at "video". These kinds of transfer speeds upon you up to interactive technologies.
It would still not be enough to stream 8k without any compression whatsover to reach lowest latency.
8k = 7680 × 4320 = 33,177,600 pixels. Each pixel can have 3 values: Red Green Blue. Each take 256 (0-255) values, which is 1 byte, which means 3 bytes just for color.
3 * 33,177,600 = 99,532,800 bytes per frame
99,532,800 bytes / 1,024 = 97,200 kilobytes
97,200 kilobytes / 1024 = ~95 megabytes
So 95MB/frame. Let's say you're streaming your screen with no compression at 60Hz or about 60 fps (minimum). That's 60*95MB/s = 5,695GB/s . Multiply that by 8 to get the bits and you're at 45,562Gb/s which is way above 25Gb/s. Hell, you wouldn't even be able to stream uncompressed 4k on that line. 2k would be possible though. I for one would like to see what an uncompressed 2k stream would look like. In the future, you could have your gaming PC at home hooked up to the internet, go anywhere with a 25Gb/s line, plop down a screen, connect it to the internet and control your computer at a distance with minimal lag as if you're right at home.
In conclusion, 25Gb wouldn't allow you to do whatever you like. You could do a lot, but there's still room. We're not at the end of the road yet.