Everything there connected via serial ports, remote offices got multiplexed over a 9600 baud connection. Back then we had local echo for the sometimes slow link, i.e. printing a spreadsheet converted to 3Mb PostScript, and still only 9600 baud in total.
So i know what local echo is. It has nothing to do with prediction :)
I'm still not convinced about mosh, but it sounds like it really does help a lot of people, so who am i to judge. I guess i'm privileged since i don't usually experience latency. We have about 95% 4G coverage in this country, coupled with fiber connections.
The last time i experienced any noticeable latency was when editing files on a clients SCO OpenServer across The Atlantic Ocean over a 1200 baud connection.
Not precisely, because you're sometimes predicting whether a keypress should be rendered as a letter on the screen or not (e.g. if you click 'j' in vim command mode it doesn't actually print j). mosh, at least from my experimentation, seems smart enough to do that reliably.
We also never have enough players for the latest FPS games that require low latency :(
As well as that and protecting unencrypted traffic on public WiFi, I get my ad blocker & other protection and credit card payments are smoother as the payment processors think I am at home not coming from some random address so doesn't ask for extra security details as often as they otherwise would.
Basically for those with experience of text terminals genrally: local echo.