At 1Gbps the internet becomes close to indistinguishable from a local network, opening up interesting possibilities like a "NAS" that's actually just the cloud. That extra bandwidth, combined with the low latency of fibre, can make it possible to easily interact with a remote PC as if it's sitting in front of you, so you could do away with a home PC or workstation and use a thin client to access a beefy machine on-demand in some datacenter.

For those use cases, latency is IMO a bigger deal than bandwidth. For remote PC, 20mbps 5ms latency would beat 10Gbps 50ms latency.

And due to the speed of light, you can't get latency arbitrarily low.

But you can dial it down pretty damn well. When I had Frontier in Texas, I rarely saw latency over 19 ms to any location in the United States. 35+ ms and I was fussy... amazing how quickly fiber can spoil a man.