Answer:
"Geosynchronous" only means it circles the Earth every 24 hours, but if it's not
also in an equatorial orbit, then it would appear to bob up and down, north and
south in the sky, every day.
I think you're really asking about "geostationary" orbit, which, in addition to
having a 24-hour period, is also over the equator, and appears motionless in
the sky.
The advantage is that anyone on the ground in the appropriate continent with
a satellite dish can mount the dish on a little tripod on their garage, and receive
signal from that satellite any time, 24/7/365. They don't need complicated and
expensive machinery to track the satellite and constantly move the dish to keep
it pointed at the bird.
Also, if the satellite moves in the sky, then for any individual person you choose,
that satellite will be down, set, not in his sky, for large portions of the time, and
the satellite is of no use to him.
If you place your satellite in an orbit that's not geosynchronous and geostationary,
then you should expect not too many paying customers to sign up for your
movie service.