The total bandwidth up/down is only part of the story.

I was on a cell modem until very recently. Just the latency difference between gigabit fiber and anything else is noticeable for me. When a website loads a ton of stuff in a single page, some of that is serialized and requests are back to back instead of parallelized. The longer the serial chain, the higher you multiply your round trip time. This is especially so with auth providers that take you away and back to a site (or similar for online purchases via external sites (eg: PayPal etc.)) All of that time adds up.

So, my home connection is now down to 11.9 ms to google.com, my wifi adds another 5ms. I did "start timeline recording" and hit the google homepage. It just took 900ms to load the front page in Safari. On a good day with my cell hotspot, my latency is 35 at idle and goes way up (sometimes in seconds) when pushing bandwidth.

Video calls with 1000ms and higher latency are ... difficult. Especially when everyone else is in the sub 100ms range.