All Naim streamers, and many others, use 100Mb Ethernet ports, partly because they are more than enough for even the highest res audio stream, but also because they use less power and generate less electrical noise than a GB port. So it’s a design choice, not just a cost cutting measure.
I think the gold rule of thumb is that if you can “easily” accomodate a wired connection, do so and turn off the streamer’s wireless interface entirely to reduce noise.
But if you can’t, then use wireless and don’t lose any sleep over the decision.