Ethernet Switch- what's the point?

I run an Ethernet cable between my router (standard issue from Verizon) and my streaming transport. I note that some use an ethernet switch between between the router and streamer. Assuming I got that right, what is the point- what does a good switch do? I've been into audio since the 70's but when its comes to streaming, I'm definitely a newbie- 

Thanks all!


@carlsbad2 you are always wrong, so there is a reason to my disagreement. 

since you think that Qobuz and others uses stateless protocols, post a pcap proving your point. 

@fredrik222 - confirmation bias is a two way street. To the extent that it applies, objectivists are just as prone to it as subjectivists.

There is a valid role for empirical observation in science otherwise we'd be stuck at "sun stand thou still upon Gibeon".

There is an interesting Live Blind Test Switches on YouTube: 

The two guys don't agree: on prefers and expensive audiophile switch and the other a standard pretty cheap switch. 

I was contemplating buying the cheaper one, but never did. 



@yoyoyaya Well, Occam's razor applies. If there is not way a switch can improve anything, which is a fact and how Ethernet and TCP/IP is designed, guess what is the next option?