You still have to go up, over, down, across wire, back up, over and down again
you're going to be paying a 25 to 50 ms latency on everything and that depends on having the dish tracking stuff working perfectly. (it is vastly better than the GEO stuff i've had to use in the past. but a replacement for fibre in general use. nope.)
oh and weather is still going to poop on your signal
the speed of light in a mostly vacuum could (provided their meshing algorithms are up to it) make latency comparable but MEO sats already have a 125ms rtt time halving that distance isn't going to get rid of that penalty.
Sorry, was being an idiot. Latency does of course tend to mean a round trip, not just here to there.
"Why SpaceX is Making Starlink"
TL;DR -- satellites can be faster than cables in certain cases
Also marketing videos are always going to show best theoretical case. They are not going to show a cloudy day in a high contention network in a region not favoured by the orbit gods.