Only place I saw 2.5G actually be beneficial is Wi-Fi 6E/7 for the APs.
Personally, I'm rarely "surprised" by a need to play a specific game that I don't already have downloaded/installed so I can just tell Steam to download the game in advance. But if I were to be in such a surprise scenario, we're talking the difference between popping on one youtube video while I wait or popping on two youtube videos while I wait. In both scenarios, I am waiting for a small but not insignificant amount of time... now if we could get 10gbps that'd be a game changer. I wouldn't even context switch for a 2.6 minute wait.
[0] https://gameboost.com/blog/call-of-duty-bo7-download-size
Now, I don't want to overstate it: it's simple disappointment. I'm still interested in the machine, as is.
Now I envy you living in a country where an internet uplink speed of > 1GbE exists for typical private households.
Fairly common for those with full-powered gaming desktops and Steam Decks, and soon, Steam Machines.
Personally... my internet is only 300 Mbps. My WiFi connection is roughly on par with 1GbE. I have a very small pool of 2.5GbE capable devices, but overall I'm just not fussed about making the switch.