I think you miss the point I was trying to make.
Gigabit ethernet is a technical standard to which it should conform if wants to describe itself as Gigabit Ethernet. It sounds like it does.
There’s nothing in the Gigabit ethernet standard to dictate the transfer speed of applications, other than (obviously) you won’t exceed 1Gbps.
In practical terms, assuming a gigabit device had a price premium, I’d be disappointed if such a device failed to exceed 100Mbps over a gigabit link. Else I might as well have bought a cheaper one. But anything decently above 100Mbps, say 300 Mbps, would leave me thinking the money was well spent - achieving speeds far in excess of the lesser 100Mbps device.