^ Yep, but you are mostly connected to a shared switch I believe, and if you have noisy neighbours your throughput can go down.
In a normal shared ethernet connection, their uplink is probably at 1 Gbps as most ONTs just have a 1 Gbps port, and I am sure they'd over provision that switch more than the available capacity. I haven't seen what type of devices they use for these shared installations, but it would probably be some relatively cheaper grade devices.
I guess in those cases it does help, atleast you are guaranteed the 1 Gbps till their OLT device.