Having been telling this to my family and friends whenever they want to upgrade to 1Gb/s, but to noavail. They rarely ever take the suggestion (ah well, to each their own).
I lived with about 5 people and our internet was 500mbps and it was more than enough.
Looking at the network monitor the only need for anything really above 100mbps was when people wanted to download something. For daily needs, surfing, browsing, the odd download you don't need a lot. And that's with everyone streaming, scrolling, gaming etc concurrently.
Btw, what network monitor are you using? Was it just a diagnostic tool in your router's admin page? Or is it something special like dd-wrt? Because seems like it's kind of hit or miss if a router's stock admin includes a reliable network monitor.
That's not really the point of the topic though right, it's that in the UK I have the choice of a billion different ISPs, including (I think stupidly) three different fibre providers (I literally have two fibre connections to my house because I changed ISPs and they ran on different fibre networks), and in the US all I hear about is streamers complaining that they are all stuck with the same shitty ISP as there is no choice, in a country that supposedly champions choice.
The main benefit, though, is if you have many simultaneous connections running, all using a lot of bandwidth.